DSE Mathematics · Core

Past paper questions

Sample · Practise · Paper 1 & Paper 2 · 2012–2024

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2017 · Paper 1 Q1 Formulae
(a) Make yy the subject of the formula k=3xyyk=\frac{3x-y}{y}. (3 marks)
2017 · Paper 1 Q2 Laws of integral indices
(a) Simplify (m4n1)3(m2)5 \frac{(m^{4}n^{-1})^{3}}{(m^{-2})^{5}} and express your answer with positive indices.
2017 · Paper 1 Q3 Polynomials
Factorize
(a)
(i) x24xy+3y2x^{2}-4xy+3y^{2}
(ii) x24xy+3y2+11x33yx^{2}-4xy+3y^{2}+11x-33y. (3 marks)
2017 · Paper 1 Q4 Linear equations in two unknowns
There are only two kinds of admission tickets for a theatre: regular tickets and concessionary tickets. The prices of a regular ticket and a concessionary ticket are \126and and \7878 respectively. On a certain day, the number of regular tickets sold is 5 times the number of concessionary tickets sold and the sum of money for the admission tickets sold is \50,976$. Find the total number of admission tickets sold that day. (4 marks)
2017 · Paper 1 Q5 Linear inequalities in one unknown
(a) Find the range of values of xx which satisfy both 7(x2)11x+837(x-2)\leq\frac{11x+8}{3} and 6x<56-x<5.
(b) How many integers satisfy both inequalities in (a)?

(4 marks)
2017 · Paper 1 Q6 Equations of straight lines
(a) Write down the coordinates of AA' and BB'.
(b) Prove that ABAB is perpendicular to ABA'B'.

(4 marks)
2017 · Paper 1 Q7 Presentation of data
The pie chart below shows the distribution of the seasons of birth of the students in a school.

Distribution of the seasons of birth of the students in the school

If a student is randomly selected from the school, then the probability that the selected student was born in spring is 19\frac{1}{9}.
Figure
(a) Find xx.
(b) In the school, there are 180180 students born in winter. Find the number of students in the school. (4 marks)
2017 · Paper 1 Q8 Variations
It is given that yy varies inversely as x\sqrt{x}. When x=144x=144, y=81y=81.
(a) Express yy in terms of xx.
(b) If the value of xx is increased from 144144 to 324324, find the change in the value of yy. (5 marks)
2017 · Paper 1 Q9 Errors in measurement
(a) Find the least possible capacity of a standard bottle.
(b) Someone claims that the total capacity of 120120 standard bottles can be measured as 23.323.3 L correct to the nearest 0.10.1 L. Do you agree? Explain your answer. (5 marks)
2017 · Paper 1 Q10 Congruent triangles
In Figure 1, OPQROPQR is a quadrilateral such that OP=OQ=OROP = OQ = OR. OQOQ and PRPR intersect at the point SS. SS is the mid-point of PRPR.
Figure
(a) Prove that ΔOPSΔORS\Delta OPS \cong \Delta ORS.
(i)
(b) It is given that OO is the centre of the circle which passes through PP, QQ and RR. If OQ=6OQ=6 cm and PRQ=10\angle PRQ=10^{\circ}, find the area of the sector OPQROPQR in terms of π\pi.
(i)
2017 · Paper 1 Q11 Measures of dispersion
The stem-and-leaf diagram below shows the distribution of the hourly wages (in dollars) of the workers in a group.

Stem (tens) | Leaf (units)
6 | 1 1 1 3 4 6 8 9 9
7 | a 7 7 8
8 | 1 b

It is given that the mean and the range of the above distribution are 70and70 and 22 respectively.
(a) Find the median and the standard deviation of the above distribution. (5 marks)
(b) If a worker is randomly selected from the group, find the probability that the hourly wage of the selected worker exceeds $70 . (2 marks)
2017 · Paper 1 Q12 Mensuration
A solid metal right prism of base area 84extcm284 ext{ cm}^{2} and height 20extcm20 ext{ cm} is melted and recast into two similar solid right pyramids. The bases of the two pyramids are squares. The ratio of the base area of the smaller pyramid to the base area of the larger pyramid is 4:94:9.
(a) Find the volume of the larger pyramid. (3 marks)
(b) If the height of the larger pyramid is 12extcm12 ext{ cm}, find the total surface area of the smaller pyramid. (4 marks)
2017 · Paper 1 Q13 Equations of circles
The coordinates of the points EE, FF and GG are (6,5)(-6,5), (3,11)(-3,11) and (2,1)(2,-1) respectively. The circle CC passes through EE and the centre of CC is GG.
(a) Find the equation of CC.
(b) Prove that FF lies outside CC. (2 marks)
(c) Let HH be a moving point on CC. When HH is farthest from FF,
(i) describe the geometric relationship between FF, GG and HH;
(ii) find the equation of the straight line which passes through FF and HH.
2017 · Paper 1 Q14 More about polynomials
(a) Find aa.
(b) Let g(x)g(x) be a quadratic polynomial such that when g(x)g(x) is divided by 2x2+ax+42x^{2} + ax + 4, the remainder is bx+cbx + c.
(i) Prove that f(x)g(x)f(x) - g(x) is divisible by 2x2+ax+42x^{2} + ax + 4.
(ii) Someone claims that all the roots of the equation f(x)g(x)=0f(x) - g(x) = 0 are integers. Do you agree? Explain your answer. (5 marks)
2017 · Paper 1 Q15 Exponential and logarithmic functions
Let aa and bb be constants. Denote the graph of y=a+logbxy = a + \log_{b}x by GG. The xx-intercept of GG is 9 and GG passes through the point (243,3)(243, 3).
() Express xx in terms of yy. (4 marks)
2017 · Paper 1 Q16 Arithmetic and geometric sequences and their summations
A city adopts a plan to import water from another city. It is given that the volume of water imported in the 1st year since the start of the plan is 1.5×107m3 1.5 \times 10^7 \, \text{m}^3 and in subsequent years, the volume of water imported each year is 10%10\% less than the volume of water imported in the previous year.
(a) Find the total volume of water imported in the first 20 years since the start of the plan. (2 marks)
(b) Someone claims that the total volume of water imported since the start of the plan will not exceed 1.6×108 1.6 \times 10^{8} m 3 ^{3} . Do you agree? Explain your answer. (2 marks)
2017 · Paper 1 Q17 More about probability
(a) find the probability that exactly 4 green pens are drawn; (2 marks)
(b) find the probability that exactly 3 green pens are drawn; (2 marks)
(c) find the probability that exactly 5 green pens are drawn. (2 marks)
(d) find the probability that not more than 2 green pens are drawn. (2 marks)
2017 · Paper 1 Q18 More about equations
The equation of the parabola Γ\Gamma is y=2x22kx+2x3k+8y=2x^{2}-2kx+2x-3k+8, where kk is a real constant. Denote the straight line y=19y=19 by LL.
(a) Prove that LL and Γ\Gamma intersect at two distinct points. (3 marks)
(b) The points of intersection of LL and Γ\Gamma are AA and BB.
(i) Let aa and bb be the xx-coordinates of AA and BB respectively. Prove that (ab)2=k2+4k+23(a-b)^{2}=k^{2}+4k+23.
(ii) Is it possible that the distance between AA and BB is less than 44? Explain your answer. (5 marks)
2017 · Paper 1 Q19 Trigonometry
ABC is a thin triangular metal sheet, where BC=24 cmBC = 24\text{ cm}, BAC=30\angle BAC = 30^\circ and ACB=42\angle ACB = 42^\circ.
Figure
(a) Find the length of ACAC.

(2 marks)
(b) In Figure 2, the thin metal sheet ABCABC is held such that only the vertex BB lies on the horizontal ground. DD and EE are points lying on the horizontal ground vertically below the vertices AA and CC respectively. ACAC produced meets the horizontal ground at the point FF. A craftsman finds that AD=10 cmAD=10\text{ cm} and CE=2 cmCE=2\text{ cm}.
Figure
(i) Find the distance between CC and FF.
(ii) Find the area of ΔABF\Delta ABF.
(iii) Find the inclination of the thin metal sheet ABCABC to the horizontal ground.
(iv) The craftsman claims that the area of ΔBDF\Delta BDF is greater than 460 cm2460\text{ cm}^{2}. Do you agree?

(11 marks)
2018 · Paper 1 Q1 Formulae
() Make bb the subject of the formula a+43=b+12\frac{a+4}{3}=\frac{b+1}{2}. (3 marks)
2018 · Paper 1 Q2 Laws of integral indices
() Simplify xy7(x2y3)4 \frac{xy^7}{(x^{-2}y^3)^4} and express your answer with positive indices. (3 marks)
2018 · Paper 1 Q3 Approximate values and numerical estimation
(a) Round up 265.473265.473 to the nearest integer.
(b) Round down 265.473265.473 to 1 decimal place.
(c) Round off 265.473265.473 to 2 significant figures. (3 marks)
2018 · Paper 1 Q4 Probability
A box contains nn white balls, 5 black balls and 8 red balls. If a ball is randomly drawn from the box, then the probability of drawing a red ball is 25\frac{2}{5}. Find the value of nn. (3 marks)
2018 · Paper 1 Q5 Polynomials
(5) Factorize

9r318r2s9r^{3}-18r^{2}s

9r318r2srs2+2s3.9r^{3}-18r^{2}s-rs^{2}+2s^{3}.

(4 marks)
2018 · Paper 1 Q6 Linear inequalities in one unknown
(a) Find the range of values of xx which satisfy both 3x2>2x+7\frac{3-x}{2}>2x+7 and x+80x+8\geq0.
(b) Write down the greatest integer satisfying both inequalities in (a).

(4 marks)
2018 · Paper 1 Q7 Using percentages
The marked price of a vase is 30%30\% above its cost. A loss of \88ismadebysellingthevaseatadiscountof is made by selling the vase at a discount of 40\%$ on its marked price. Find the marked price of the vase. (5 marks)
2018 · Paper 1 Q8 Basic properties of circles
In Figure 1, ABCDEABCDE is a circle. It is given that AB//EDAB//ED. ADAD and BEBE intersect at the point FF.
Figure
2018 · Paper 1 Q9 Rates, ratios and proportions
A car travels from city PP to city QQ at an average speed of 72 km/h72\text{ km/h} and then the car travels from city QQ to city RR at an average speed of 90 km/h90\text{ km/h}. It is given that the car travels 210 km210\text{ km} in 161161 minutes for the whole journey. How long does the car take to travel from city PP to city QQ? (5 marks)
2018 · Paper 1 Q10 Measures of dispersion
The box-and-whisker diagram below shows the distribution of the ages of the clerks in team X of a company. It is given that the range and the inter-quartile range of this distribution are 4343 and 2121 respectively.
Figure
(a) Find aa and bb.
(b) (2) There are five clerks in team Y of the company and three of them are of age 5050 or is given that the range of the ages of the clerks in team Y is 2020. Team X and team Y are now combined to form a section. The manager of the company claims that the range of the ages of the clerks in the section and the range of the ages of the clerks in team X must be the same. Do you agree? Explain your answer. (2 marks)
2018 · Paper 1 Q11 Measures of central tendency
The following table shows the distribution of the numbers of children of some families:
(a) It is given that kk is a positive integer. If the mode of the distribution is 2, write down
(i) the least possible value of kk;
(ii) the greatest possible value of kk.
(b) If the median of the distribution is 2, write down
(i) the least possible value of kk;
(ii) the greatest possible value of kk.
(c) If the mean of the distribution is 2, find the value of kk. (2 marks)
2018 · Paper 1 Q12 More about polynomials
(a) Find aa and bb.
(b) Someone claims that the equation f(x)=0f(x)=0 has at least one irrational root. Do you agree? Explain your answer. (4 marks)
2018 · Paper 1 Q13 Similar triangles
Figure
(a) Prove that ABEECD \triangle ABE \sim \triangle ECD .

(2 marks)
(b) It is given that AB=15 cmAB = 15\text{ cm}, AE=25 cmAE = 25\text{ cm} and CE=36 cmCE = 36\text{ cm}.
(i) Find the length of CDCD.
(ii) Find the area of ADE \triangle ADE .
(iii) Is there a point FF lying on ADAD such that the distance between EE and FF is less than 23 cm23\text{ cm} ? Explain your answer.

(6 marks)
2018 · Paper 1 Q14 Mensuration
(a) Find the volume of water in the vessel in terms of π\pi. (2 marks)
(b) Find the depth of water in the vessel. (4 marks)
(c) If a solid metal sphere of radius 14 cm14\text{ cm} is then put into the vessel and the sphere is totally immersed in the water, will the water overflow? Explain your answer. (3 marks)
2018 · Paper 1 Q15 Permutations and combinations
(a) How many different eight-digit phone numbers can be formed? (1 mark)
(b) If the first digit and the last digit of an eight-digit phone number are odd numbers, how many different eight-digit phone numbers can be formed? (2 marks)
2018 · Paper 1 Q16 Arithmetic and geometric sequences and their summations
The 3rd term and the 4th term of a geometric sequence are 720720 and 864864 respectively.
(a) Find the 1st1^{st} term of the sequence.

(2 marks)
(b) Find the greatest value of nn such that the sum of the (n+1)(n+1)th term and the (2n+1)(2n+1)th term is less than 5×10145 \times 10^{14}.

(3 marks)
2018 · Paper 1 Q17 Trigonometry
(a) In Figure 3(a), ABCDABCD is a paper card in the shape of a parallelogram. It is given that AB=60 cmAB = 60 \text{ cm}, ABD=20\angle ABD = 20^\circ and BAD=120\angle BAD = 120^\circ.

[Figure 3(a)]

Find the length of ADAD.
Figure
(b) The paper card in Figure 3(a) is folded along BDBD such that the distance between AA and CC is 40 cm40 \text{ cm} (see Figure 3(b)).

[Figure 3(b)]
Figure
(i) Find ABC\angle ABC.
(ii) Find the angle between the plane ABDABD and the plane BCDBCD. (5 marks)
2018 · Paper 1 Q18 Variations
It is given that f(x) f(x) partly varies as x2 x^{2} and partly varies as x. Suppose that f(2)=60 f(2)=60 and f(3)=99 f(3)=99 .
(a) Find f(x) f(x) . (3 marks)
(b) Let Q be the vertex of the graph of y=f(x) y = f(x) and R be the vertex of the graph of y=27f(x) y = 27 - f(x) .
(i) Using the method of completing the square, find the coordinates of Q.
(ii) Write down the coordinates of R.
(iii) The coordinates of the point SS are (56,0)(56, 0). Let PP be the circumcentre of ΔQRS\Delta QRS. Describe the geometric relationship between PP, QQ and RR. Explain your answer. (5 marks)
2018 · Paper 1 Q19 Equations of circles
(a) Find the equation of CC in terms of rr. Hence, express r2r^{2} in terms of kk. (4 marks)
(b) LL passes through the point D(18,39)D(18,39).
(i) Find rr.
(ii) It is given that LL cuts the yy-axis at the point EE. Let FF be a point such that CC is the inscribed circle of ΔDEF\Delta DEF. Is ΔDEF\Delta DEF an obtuse-angled triangle? Explain your answer. (8 marks)
Practise Paper · Paper 1 Q1 Laws of integral indices
Simplify (m5n2)6m4n3\frac{(m^{5}n^{-2})^{6}}{m^{4}n^{-3}} and express your answer with positive indices.
Practise Paper · Paper 1 Q2 Formulae
Make aa the subject of the formula 5+b1a=3b\frac{5+b}{1-a}=3b
Practise Paper · Paper 1 Q3 Polynomials
Factorize
Practise Paper · Paper 1 Q4 Using percentages
The cost of a chair is \360.Ifthechairissoldatadiscountof. If the chair is sold at a discount of 20\%onitsmarkedprice,thenthepercentageprofitis on its marked price, then the percentage profit is 30\%$. Find the marked price of the chair.
Practise Paper · Paper 1 Q5 Rates, ratios and proportions
The ratio of the capacity of a bottle to that of a cup is 4:34:3. The total capacity of 7 bottles and 9 cups is 1111 litres. Find the capacity of a bottle.
Practise Paper · Paper 1 Q6 Rectangular coordinate system
(a) Let OO be the pole. Are AA, OO and CC collinear? Explain your answer.
(b) Find the area of riangleABC riangle ABC.
(4 marks)
Practise Paper · Paper 1 Q7 Basic properties of circles
In Figure 1, BDBD is a diameter of the circle ABCDABCD. If AB=ACAB = AC and BDC=36\angle BDC = 36^{\circ}, find ABD\angle ABD (4 marks)
Figure
Practise Paper · Paper 1 Q8 Rectangular coordinate system
The coordinates of the points A and B are (3,4)(-3, 4) and (2,5)(-2, -5) respectively. AA' is the reflection image of A with respect to the y-axis. B is rotated anticlockwise about the origin O through 9090^{\circ} to BB'.
(a) Write down the coordinates of AA' and BB'
(b) Let PP be a moving point in the rectangular coordinate plane such that PP is equidistant from AA' and BB' . Find the equation of the locus of PP .
Practise Paper · Paper 1 Q9 Measures of dispersion
(a) Find the least possible value and the greatest possible value of the inter-quartile range of the distribution.
(b) If r=9r=9 and the median of the distribution is 33, how many possible values of ss are there? Explain your answer. (The marks line is missing from the source but the question likely ends with a marks line; since it is not present, no marks line is appended.)
Practise Paper · Paper 1 Q10 More about polynomials
(a) Find f(3)f(-3).
(b) Factorize f(x)f(x).
Practise Paper · Paper 1 Q11 Variations
Let CC be the cost of manufacturing a cubical carton of side xx cm. It is given that CC is partly constant and partly varies as the square of xx. When x=20x=20, C=42C=42; when x=120x=120, C=112C=112.
(a) Find the cost of manufacturing a cubical carton of side 50 cm 50\text{ cm }.
(b) If the cost of manufacturing a cubical carton is $58, find the length of a side of the carton. (2 marks)
Practise Paper · Paper 1 Q12 Rectangular coordinate system
Figure 2 shows the graphs for Ada and Billy running on the same straight road between town PP and town QQ during the period 1:00 to 3:00 in an afternoon. Ada runs at a constant speed. It is given that town PP and town QQ are 16 km16\text{ km} apart.
Figure
(a) How long does Billy rest during the period? (2 marks)
(b) How far from town PP do Ada and Billy meet during the period? (3 marks)
(c) Use average speed during the period to determine who runs faster. Explain your answer. (2 marks)