DSE Mathematics · Core

Past paper questions

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

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2018 · Paper 1 Q1 Formulae
(a) Make bb the subject of the formula a+43=b+12\frac{a+4}{3}=\frac{b+1}{2}.
(b) (3 marks)
2018 · Paper 1 Q2 Laws of integral indices
(a) Simplify xy7(x2y3)4\frac{xy^7}{(x^{-2}y^3)^4} and express your answer with positive indices.
(b) (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 11 decimal place.
(c) Round off 265.473265.473 to 22 significant figures. (3 marks)
2018 · Paper 1 Q4 Probability
A box contains nn white balls, 55 black balls and 88 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
Factorize
(a) 9r318r2s9r^{3}-18r^{2}s
(b) 9r318r2srs2+2s3.9 r^{3}-18 r^{2}s-r s^{2}+2 s^{3}. (4 marks)
2018 · Paper 1 Q6 Inequalities and linear programming
(a) Find the range of values of xx which satisfy both 3x2>2x+7\frac{3-x}{2}>2x+7 and x+80x+8\geq 0.
(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
(a) Express xx and yy in terms of θ\theta. (5 marks)
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) 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 Organisation of data
The following table shows the distribution of the numbers of children of some families:

[Table]

It is given that kk is a positive integer.
(a) 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
Let f(x)=4x(x+1)2+ax+bf(x)=4x(x+1)^{2}+ax+b, where aa and bb are constants. It is given that x3x-3 is a factor of f(x)f(x). When f(x)f(x) is divided by x+2x+2, the remainder is 2b+1652b+165.
(a) Find aa and bb. (3 marks)
(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
In Figure 2, ABCDABCD is a trapezium with ABC=90\angle ABC = 90^\circ and ABDCAB \parallel DC. EE is a point lying on BCBC such that AED=90\angle AED = 90^\circ.
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 right circular cylindrical container of base radius 8 cm8\text{ cm} and height 64 cm64\text{ cm} and an inverted right circular conical vessel of base radius 20 cm20\text{ cm} and height 60 cm60\text{ cm} are held vertically. The container is fully filled with water. The water in the container is now poured into the vessel.
(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 Q14 Equations of straight lines
The coordinates of the points AA, BB and CC are (4,8)(4, -8), (1,2)(-1, -2) and (2,2)(-2, 2) respectively. DD is a point lying on the line segment BCBC such that ADAD is perpendicular to BCBC. Let EE be the intersection point of ADAD and the yy-axis. Suppose that FF is a point lying on the line segment ABAB such that the area of ΔAEF\Delta AEF is 13\frac{1}{3} of the area of ΔABD\Delta ABD.
(a) Find the coordinates of DD and EE.
(b) Find the equation of the circle passing through AA, EE and FF.
2018 · Paper 1 Q15 Permutations and combinations
An eight-digit phone number is formed by a permutation of 2, 3, 4, 5, 6, 7, 8 and 9.
(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 720 and 864 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}. 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
(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 x2x^{2} and partly varies as xx. Suppose that f(2)=60f(2)=60 and f(3)=99f(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)
2018 · Paper 2 Q1 Laws of integral indices
82n+143n+1=\frac{8^{2n+1}}{4^{3n+1}} =
A 1.
B 2.
C 2n2^n.
D 2n2^{-n}.
2018 · Paper 2 Q2 Formulae
If α1x=βx\frac{\alpha}{1-x} = \frac{\beta}{x}, then x=x =
A ααβ\frac{\alpha}{\alpha - \beta}.
B αα+β\frac{\alpha}{\alpha + \beta}.
C βαβ\frac{\beta}{\alpha - \beta}.
D βα+β\frac{\beta}{\alpha + \beta}.
2018 · Paper 2 Q3 More about polynomials
h26h4k212k=h^2 - 6h - 4k^2 - 12k =
A (h2k)(h2k+6)(h-2k)(h-2k+6).
B (h2k)(h+2k+6)(h-2k)(h+2k+6).
C (h+2k)(h2k6)(h+2k)(h-2k-6).
D (h+2k)(h+2k6)(h+2k)(h+2k-6).
2018 · Paper 2 Q4 Algebraic expressions
13x+713x7=\frac{1}{3x+7}-\frac{1}{3x-7}=
A 14499x2\frac{14}{49-9x^{2}}.
B 149x249\frac{14}{9x^{2}-49}.
C 6x499x2\frac{6x}{49-9x^{2}}.
D 6x9x249\frac{6x}{9x^{2}-49}.
2018 · Paper 2 Q5 More about graphs of functions
Which of the following statements about the graph of y=16(x6)2y=16-(x-6)^{2} is true?
A The graph cuts the x-axis.
B The graph opens upwards.
C The y-intercept of the graph is 16.
D The graph passes through the origin.
2018 · Paper 2 Q6 Equations of straight lines
In the figure, the equations of the straight lines L1L_{1} and L2L_{2} are 3x+ay=b3x + ay = b and cx+y=dcx + y = d respectively. Which of the following is/are true?
Figure
I ac<3ac < 3
II ad<bad < b
III bc<3dbc < 3d
A II only
B III only
C I and II only
D I and III only
2018 · Paper 2 Q7 Functions and graphs
If f(x)=3x22x+1f(x)=3x^{2}-2x+1, then f(2m1)=f(2m-1)=
A 6m24m+26m^{2}-4m+2
B 6m24m+66m^{2}-4m+6
C 12m216m+212m^{2}-16m+2
D 12m216m+612m^{2}-16m+6
2018 · Paper 2 Q8 More about polynomials
Let g(x)=x8+ax7+bg(x)=x^{8}+ax^{7}+b, where aa and bb are constants. If g(x)g(x) is divisible by x1x-1, find the remainder when g(x)g(x) is divided by x+1x+1.
A 00
B 2a2a
C 2a-2a
D 2a+2-2a+2
2018 · Paper 2 Q9 Using percentages
A sum of \100\,000isdepositedataninterestrateof is deposited at an interest rate of 2\%perannumfor per annum for 3$ years, compounded monthly. Find the interest correct to the nearest dollar.
A \6000$
B \6121$
C \6176$
D \6178$
2018 · Paper 2 Q10 Rates, ratios and proportions
Let aa, bb and cc be non-zero numbers. If 3a=4b3a = 4b and a:c=2:5a:c = 2:5, then a+3bb+3c=\frac{a+3b}{b+3c} =
A 53\frac{5}{3}.
B 1333\frac{13}{33}.
C 3053\frac{30}{53}.
D 7538\frac{75}{38}.
2018 · Paper 2 Q11 Variations
If ww varies directly as the square root of uu and inversely as the square of vv, which of the following must be constant?
A u4vw2u^{4}v w^{2}.
B uv4w2uv^{4}w^{2}.
C vw2u4\frac{v w^{2}}{u^{4}}.
D v4w2u\frac{v^{4}w^{2}}{u}.
2018 · Paper 2 Q12 Arithmetic and geometric sequences and their summations
Let ana_n be the nnth term of a sequence. If a3=21a_3 = 21, a6=89a_6 = 89 and an+2=an+an+1a_{n+2} = a_n + a_{n+1} for any positive integer nn, then a1=a_1 =
A 8.
B 13.
C 34.
D 55.
2018 · Paper 2 Q13 Inequalities and linear programming
The solution of 12x3qx3\frac{1-2x}{3} \ge q x-3 or 4x+9<14x+9 < 1 is
A x<2x < -2
B x>2x > -2
C xq2x \le q 2
D xq2x \ge q 2
2018 · Paper 2 Q14 Errors in measurement
In the figure, ABCDEFGH is an octagon, where all the measurements are correct to the nearest cm. Let xcm2x \, cm^2 be the actual area of the octagon. Find the range of values of x.
Figure
A 13<x<2313 < x < 23
B 13<x<2713 < x < 27
C 17<x<2317 < x < 23
D 17<x<2717 < x < 27
2018 · Paper 2 Q15 Mensuration
In the figure, the volume of the solid right triangular prism is
Figure
A 544 cm3544\text{ cm}^{3}.
B 600 cm3600\text{ cm}^{3}.
C 660 cm3660\text{ cm}^{3}.
D 720 cm3720\text{ cm}^{3}.
2018 · Paper 2 Q16 Centres of triangles
In the figure, ABCDABCD is a parallelogram. EE is a point lying on BCBC such that BE:EC=5:3BE:EC = 5:3. AEAE and BDBD intersect at the point FF. If the area of ABF\triangle ABF is 120 cm2120\ cm^{2}, then the area of the quadrilateral CDFECDFE is
Figure
A 237 cm2237\text{ cm}^{2}.
B 307 cm2307\text{ cm}^{2}.
C 312 cm2312\text{ cm}^{2}.
D 429 cm2429\text{ cm}^{2}.
2018 · Paper 2 Q17 Arc lengths and areas of sectors
In the figure, OO is the centre of the sector OABCDOABCD. ADAD and OCOC are perpendicular to each other and intersect at the point EE. FF is a point lying on ADAD such that BFBF is perpendicular to ADAD. If AF=9AF = 9 cm, DF=39DF = 39 cm and OE=18OE = 18 cm, then the area of the sector OBCOBC is
Figure
A 48π cm248\pi\text{ cm}^{2}.
B 75π cm275\pi\text{ cm}^{2}.
C 96π cm296\pi\text{ cm}^{2}.
D 150π cm2150\pi\text{ cm}^{2}.
2018 · Paper 2 Q18 Quadrilaterals
In the figure, ABCDABCD is a rhombus. EE and FF are points lying on ABAB and ADAD respectively such that AE=AFAE = AF and ECF=42\angle ECF = 42^{\circ}. If BAD=110\angle BAD = 110^{\circ}, then BEC=\angle BEC =
Figure
2018 · Paper 2 Q19 Quadrilaterals
In the figure, ABCDEABCDE is a regular pentagon. ADAD and CECE intersect at the point FF. Which of the following are true?
I. CD=CFCD = CF
II. ΔABFΔCBF\Delta ABF \cong \Delta CBF
III. AFB+EAF=90\angle AFB + \angle EAF = 90^{\circ}
Figure
A I and II only
B I and III only
C II and III only
D I, II and III
2018 · Paper 2 Q20 Similar triangles
In the figure, ABCDABCD is a square. EE is a point lying on ABAB produced such that BE=4BE = 4 cm. BCBC and DEDE intersect at the point FF. If EF=5EF = 5 cm, then DF=DF =
Figure
A 1212 cm.
B 1515 cm.
C 1616 cm.
D 2020 cm.
2018 · Paper 2 Q21 Trigonometry
In the figure, ABCDABCD is a trapezium with ABC=BAD=90\angle ABC = \angle BAD = 90^{\circ}. EE and FF are points lying on ABAB such that EE and FF divide ABAB into three equal parts. Which of the following must be true?

I. AFsinα=BEsinβAF\sin\alpha=BE\sin\beta

II. CEcosα=DFcosβCE\cos\alpha=DF\cos\beta

III. ADtanα=BCtanβAD\tan\alpha=BC\tan\beta
A I and II only
B I and III only
C II and III only
D I, II and III
2018 · Paper 2 Q22 Basic properties of circles
In the figure, ABCDABCD is a circle. ADAD produced and BCBC produced meet at the point EE. It is given that BD=DEBD=DE, BAC=66\angle BAC=66^{\circ} and ABD=30\angle ABD=30^{\circ}. Find CED\angle CED.
FigureFigure
A 20 20^{\circ}
B 28 28^{\circ}
C 36 36^{\circ}
D 42 42^{\circ}
2018 · Paper 2 Q23 Polygons
The figure below consists of eight identical squares. The number of folds of rotational symmetry of the figure is
Figure
A 2.
B 4.
C 6.
D 8.
2018 · Paper 2 Q24 Trigonometry
The polar coordinates of the points CC, DD and EE are (16,127)(16, 127^{\circ}), (12,217)(12, 217^{\circ}) and (5,307)(5, 307^{\circ}) respectively. Find the perimeter of ΔCDE\Delta CDE.
A 5454.
B 7878.
C 126126.
D 130130.
2018 · Paper 2 Q25 Loci
The equations of the straight lines L1L_{1} and L2L_{2} are 3xy+7=03x - y + 7 = 0 and 12x4y11=012x - 4y - 11 = 0 respectively. Let PP be a moving point in the rectangular coordinate plane such that the perpendicular distance from PP to L1L_{1} is equal to the perpendicular distance from PP to L2L_{2}. Find the equation of the locus of PP.
A 8x24y17=08x - 24y - 17 = 0
B 8x24y+17=08x - 24y + 17 = 0
C 24x8y17=024x - 8y - 17 = 0
D 24x8y+17=024x - 8y + 17 = 0
2018 · Paper 2 Q26 Equations of straight lines
The equation of the straight line L1L_{1} is 4x+3y36=04x + 3y - 36 = 0. The straight line L2L_{2} is perpendicular to L1L_{1} and intersects L1L_{1} at a point lying on the yy-axis. Find the area of the region bounded by L1L_{1}, L2L_{2} and the xx-axis.
A 9696.
B 108108.
C 150150.
D 192192.
2018 · Paper 2 Q27 Equations of circles
The equation of the circle CC is 5x2+5y230x+10y+6=05x^{2}+5y^{2}-30x+10y+6=0. Which of the following is true?
A The origin lies inside CC.
B CC lies in the second quadrant.
C The circumference of CC is less than 2020.
D The coordinates of the centre of CC are (15,5)(15, -5).
2018 · Paper 2 Q28 More about probability
Two numbers are randomly drawn at the same time from seven cards numbered 1, 1, 1, 2, 2, 3 and 4 respectively. Find the probability that the sum of the numbers drawn is 5.
A 521\frac{5}{21}
B 542\frac{5}{42}
C 549\frac{5}{49}
D 1049\frac{10}{49}
2018 · Paper 2 Q29 Measures of dispersion
The mean of the numbers of pages of 10 magazines is 132. If the mean of the numbers of pages of 6 of these 10 magazines is 108, then the mean of the numbers of pages of the remaining 4 magazines is
A 148.
B 156.
C 168.
D 176.
2018 · Paper 2 Q30 Measures of dispersion
The stem-and-leaf diagram below shows the distribution of the numbers of books read by 20 students in a year.

Stem\textsc(tens)Leaf\textsc(units)83aa40245578536bb99708 \begin{array}{c|ccccc}{{\underline{S t e m}\textsc{(t e n s)}}}&{{\underline{L e a f}\textsc{(units)}}}&{{{8}}} \\{{{3}}}&{{{a}}}&{{{a}}} \\{{{4}}}&{{{0}}}&{{{2}}}&{{{4}}}&{{{5}}}&{{{5}}}&{{{7}}}&{{{8}}} \\{{{5}}}&{{{3}}} \\{{{6}}}&{{{b}}}&{{{b}}}&{{{9}}}&{{{9}}} \\{{{7}}}&{{{0}}}&{{{8}}} \\\end{array}

If the inter-quartile range of the above distribution is at most 2525, which of the following must be true

I. 5qaq95 \le q a \le q 9
II. 0qbq40 \le q b \le q 4
III. 1qabq61 \le q a - b \le q 6
A I and II only
B I and III only
C II and III only
D I, II and III