DSE Mathematics · Core

Past paper questions

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

Topic
38 questions match · Clear all
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)
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)
Practise Paper · Paper 1 Q13 Presentation of data
The bar chart below shows the distribution of the most favourite fruits of the students in a group. It is given that each student has only one most favourite fruit.

Distribution of the most favourite fruits of the students in the group

If a student is randomly selected from the group, then the probability that the most favourite fruit is apple is 320\frac{3}{20}.
Figure
(a) Find kk.

(3 marks)
(b) Suppose that the above distribution is represented by a pie chart.
(i) Find the angle of the sector representing that the most favourite fruit is orange.
(ii) Some new students now join the group and the most favourite fruit of each of these students is orange. Will the angle of the sector representing that the most favourite fruit is orange be doubled? Explain your answer.

(4 marks)
Practise Paper · Paper 1 Q14 Basic properties of circles
In Figure 3, OABCOABC is a circle. It is given that ABAB produced and OCOC produced meet at DD.
Figure
(a) Write down a pair of similar triangles in Figure 3.

(2 marks)
(b) Suppose that AOD=90\angle AOD = 90^{\circ}. A rectangular coordinate system, with OO as the origin, is introduced in Figure 3 so that the coordinates of AA and DD are (6,0)(6,0) and (0,12)(0,12) respectively. If the ratio of the area of BCD\triangle BCD to the area of OAD\triangle OAD is 16:4516:45, find
(i) the coordinates of CC,
(ii) the equation of the circle OABCOABC.

(7 marks)
Practise Paper · Paper 1 Q15 Measures of dispersion
(a) Find the standard score of John in the test. (2 marks)
(b) A student, David, withdraws from the class and his test score is then deleted. It is given that his test score is 4848 marks. Will there be any change in the standard score of John due to the deletion of the test score of David? Explain your answer. (2 marks)
Practise Paper · Paper 1 Q16 Probability
There are 18 boys and 12 girls in a class. From the class, 4 students are randomly selected to form the class committee.
(a) Find the probability that the class committee consists of boys only. (2 marks)
(b) Find the probability that the class committee consists of at least 11 boy and 1 girl. (2 marks)
Practise Paper · Paper 1 Q17 More about equations
(a) Express 11+2i\frac{1}{1+2i} in the form of a+bia+bi, where aa and bb are real numbers.

(2 marks)
(b) The roots of the quadratic equation x2+px+q=0x^{2}+px+q=0 are 101+2i\frac{10}{1+2i} and 1012i\frac{10}{1-2i}. Find
(i) pp and qq,

(2 marks)
(ii) the range of values of rr such that the quadratic equation x2+px+q=rx^{2}+px+q=r has real roots.

(2 marks)
Practise Paper · Paper 1 Q18 More about trigonometry
Figure 4 shows a geometric model ABCDABCD in the form of tetrahedron. It is found that ACB=60\angle ACB = 60^{\circ}, AC=AD=20AC = AD = 20 cm, BC=BD=12BC = BD = 12 cm and CD=14CD = 14 cm.
Figure
(a) Find the length of ABAB.

(2 marks)
(b) Find the angle between the plane ABCABC and the plane ABDABD.

(4 marks)
(c) Let PP be a movable point on the slant edge ABAB. Describe how CPD\angle CPD varies as PP moves from AA to BB. Explain your answer.

(2 marks)
Practise Paper · Paper 1 Q19 Arithmetic and geometric sequences and their summations
(a) Find rr.

(2 marks)
(b) The revenue made by the firm in the 1st year is \2000000.Therevenuemadeineachsuccessiveyearis. The revenue made in each successive year is 20\%$ less than the previous year.
(i) Find the least number of years needed for the total revenue made by the firm to exceed \9000000$.
(ii) Will the total revenue made by the firm exceed \10000000$? Explain your answer.
(iii) The manager of the firm claims that the total revenue made by the firm will exceed the total amount of investment. Do you agree? Explain your answer. (10 marks)