DSE Mathematics · Core

Past paper questions

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

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2019 · Paper 1 Q1 Formulae
Make hh the subject of the formula 9(h+6k)=7h+89(h+6k)=7h+8.
2019 · Paper 1 Q2 Algebraic expressions
Simplify 37x625x4\frac{3}{7x-6}-\frac{2}{5x-4}.
2019 · Paper 1 Q3 Pythagoras' theorem
The length and the breadth of a rectangle are 24 cm24\text{ cm} and (13+r) cm(13+r)\text{ cm} respectively. If the length of a diagonal of the rectangle is (173r) cm(17-3r)\text{ cm}, find rr.
() The length and the breadth of a rectangle are 24 cm24\text{ cm} and (13+r) cm(13+r)\text{ cm} respectively. If the length of a diagonal of the rectangle is (173r) cm(17-3r)\text{ cm}, find rr. (3 marks)
2019 · Paper 1 Q4 More about polynomials
(a) Factorize

4m294m^{2}-9
(b) Factorize

2m2n+7mn15n2m^{2}n+7mn-15n
(c) Factorize

4m292m2n7mn+15n4m^{2}-9-2m^{2}n-7mn+15n
(4 marks)
2019 · Paper 1 Q5 Using percentages
(a) Find the marked price of the wallet.
(b) After selling the wallet, the percentage profit is 15%15\%. Find the cost of the wallet. (4 marks)
2019 · Paper 1 Q6 Linear inequalities in one unknown
(a) Solve the inequality 7x+2642(3x1)\frac{7x+26}{4}\leq2(3x-1).
(b) Find the number of integers satisfying both inequalities 7x+2642(3x1)\frac{7x+26}{4}\leq2(3x-1) and 455x045-5x\geq0. (4 marks)
2019 · Paper 1 Q7 Rates, ratios and proportions
In a playground, the ratio of the number of adults to the number of children is 13:613:6. If 99 adults and 2424 children enter the playground, then the ratio of the number of adults to the number of children is 8:78:7. Find the original number of adults in the playground. (4 marks)
2019 · Paper 1 Q8 Organisation of data
Figure
(a) Write down the mode of the distribution.
(b) Find the mean of the distribution.
(c) If a girl is randomly selected from the group, find the probability that the selected girl owns more than 3 rings. (5 marks)
2019 · Paper 1 Q9 Mensuration
(a) the volume of the larger sphere;
(b) the sum of the surface areas of the two spheres. (5 marks)
2019 · Paper 1 Q11 More about polynomials
Let p(x)p(x) be a cubic polynomial. When p(x)p(x) is divided by x1x-1, the remainder is 5050. When p(x)p(x) is divided by x+2x+2, the remainder is 52-52. It is given that p(x)p(x) is divisible by 2x2+9x+142x^{2}+9x+14.
(a) Find the quotient when p(x)p(x) is divided by 2x2+9x+142x^{2}+9x+14.
(b) How many rational roots does the equation p(x)=0p(x)=0 have? Explain your answer. (3 marks)
2019 · Paper 1 Q12 Measures of dispersion
(a) Find cc. (2 marks)
(b) It is given that the range of the distribution exceeds 3434 seconds and the mean of the distribution is 6969 seconds. Find
(i) aa and bb, (6 marks)
(ii) the least possible standard deviation of the distribution. (6 marks)
2019 · Paper 1 Q13 Basic properties of circles
Figure
(a) Find CBF \angle CBF .
(b) Suppose that BC//ODBC//OD and OB=18OB=18cm. Is the perimeter of the sector OBCOBC less than 6060 cm? Explain your answer. (5 marks)
2019 · Paper 1 Q14 Similar triangles
Figure
(a) Prove that
(i) ΔBCGΔCBF\Delta BCG \cong \Delta CBF
(ii) ΔBCFΔDEF\Delta BCF \sim \Delta DEF
(b) Suppose that BCF=BGC\angle BCF = \angle BGC
(i) Let BC=BC = \ell. Express DFDF in terms of \ell.
(ii) Someone claims that AE>DFAE > DF. Do you agree? Explain your answer. (4 marks)
2019 · Paper 1 Q15 Permutations and combinations
(a) It is students are selected from the class to form a committee consisting of at least 11 boy, how many different committees can be formed? (3 marks)
2019 · Paper 1 Q16 Arithmetic and geometric sequences and their summations
(a) Find α \alpha and β \beta .

(2 marks)
(b) The 1st term and the 2nd term of an arithmetic sequence are logα \log\alpha and logβ \log\beta respectively.

Find the least value of nn such that the sum of the first nn terms of the sequence is greater than 888888.

(4 marks)
2019 · Paper 1 Q17 Equations of straight lines
(a) Let aa and pp be the area and the perimeter of CDE\triangle CDE respectively. Denote the radius of the inscribed circle of CDE\triangle CDE by rr. Prove that pr=2apr = 2a. (2 marks)
(b) The coordinates of the points H and K are (9,12)(9,12) and (14,0)(14,0) respectively. Let P be a moving point in the rectangular coordinate plane such that the perpendicular distance from P to OH is equal to the perpendicular distance from P to HK, where O is the origin. Denote the locus of P by Γ\Gamma.
(i) Describe the geometric relationship between Γ\Gamma and OHK\angle OHK.
(ii) Using (a), find the equation of Γ\Gamma (5 marks)
2019 · Paper 1 Q18 3-D figures
Figure
(a)
(i) BAD\angle BAD.
(ii) CPCP.
(b) The craftsman claims that BPC\angle BPC is the angle between the face ABDABD and the face ACDACD. Is the claim correct? Explain your answer. (2 marks)
2019 · Paper 1 Q19 More about graphs of functions
Let f(x)=11+k(x2+(6k2)x+(9k+25))f(x)=\frac{1}{1+k}\left(x^{2}+(6k-2)x+(9k+25)\right), where kk is a positive constant. Denote the point (4,33)(4,33) by FF.
(a) Prove that the graph of y=f(x)y = f(x) passes through FF.
(b) The graph of y=g(x)y = g(x) is obtained by reflecting the graph of y=f(x)y = f(x) with respect to the yy-axis and then translating the resulting graph upwards by 44 units. Let UU be the vertex of the graph of y=g(x)y = g(x). Denote the origin by OO.
(i) Using the method of completing the square, express the coordinates of UU in terms of kk.
(ii) Find kk such that the area of the circle passing through FF, OO and UU is the least.
(iii) For any positive constant kk, the graph of y=g(x)y = g(x) passes through the same point GG. Let VV be the vertex of the graph of y=g(x)y = g(x) such that the area of the circle passing through FF, OO and VV is the least. Are FF, GG, OO and VV concyclic? Explain your answer.
2019 · Paper 2 Q1 Polynomials
(ab)(a2+abb2)=(a-b)(a^{2}+ab-b^{2}) =
A (ab)3 (a-b)^{3}
B a3b3 a^{3}-b^{3}
C a32ab2+b3 a^{3}-2ab^{2}+b^{3}
D a32a2b+2ab2+b3 a^{3}-2a^{2}b+2ab^{2}+b^{3}
2019 · Paper 2 Q2 Laws of integral indices
(6x7)24x5=\frac{(6x^7)^2}{4x^5} =
A 3x4 3x^4 .
B 9x4 9x^4 .
C 3x9 3x^9 .
D 9x9 9x^9 .
2019 · Paper 2 Q3 Linear equations in two unknowns
If 6x7y=40=2x+11y 6x - 7y = 40 = 2x + 11y , then y=y =
A 4-4.
B 22.
C 44.
D 99.
2019 · Paper 2 Q4 Identities
If α \alpha and β \beta are constants such that (x8)(x+α)6(x9)2+β (x-8)(x+\alpha)-6\equiv(x-9)^2+\beta , then β= \beta=
A 26 -26
B 10 -10
C 7 -7
D 6 -6
2019 · Paper 2 Q5 Formulae
If h=35k+4h = 3 - \frac{5}{k + 4}, then k=k =
A 4h73h\frac{4h-7}{3-h}
B 4h173h\frac{4h-17}{3-h}
C 4h73+h\frac{4h-7}{3+h}
D 4h173+h\frac{4h-17}{3+h}
2019 · Paper 2 Q6 Approximate values and numerical estimation
If 0.06557<x<0.065640.06557 < x < 0.06564, which of the following is true?
A x=0.065x = 0.065 (correct to 2 decimal places)
B x=0.065x = 0.065 (correct to 2 significant figures)
C x=0.0656x = 0.0656 (correct to 3 decimal places)
D x=0.0656x = 0.0656 (correct to 3 significant figures)
2019 · Paper 2 Q7 Linear inequalities in one unknown
The least integer satisfying the compound inequality 2(x5)+5<21-2(x-5)+5<21 or 3x57>1\frac{3x-5}{7}>1 is
A 3-3.
B 2-2.
C 44.
D 55.
2019 · Paper 2 Q8 Polynomials
Let cc be a constant. If f(x)=x3+cx2+cf(x) = x^3 + cx^2 + c, then f(c)+f(c)=f(c) + f(-c) =
A 00.
B 2c2c.
C 2c3+2c2c^3 + 2c.
D 2c3+2c-2c^3 + 2c.
2019 · Paper 2 Q9 More about polynomials
Let kk be a constant such that 2x4+kx34x162x^{4} + kx^{3} - 4x - 16 is divisible by 2x+k2x + k. Find kk.
A 2-2.
B 22.
C 44.
D 88.
2019 · Paper 2 Q10 More about graphs of functions
Which of the following statements about the graph of y=(3x)(x+2)+6y=(3-x)(x+2)+6 is/are true?

I. The graph opens downwards.

II. The graph passes through the point (1,10)(1,10).

III. The xx-intercepts of the graph are 2-2 and 33.

A. I only

B. II only

C. I and III only

D. II and III only
A 11 only.
B II\text{II} only.
C I\text{I} and III\text{III} only.
D II\text{II} and III\text{III} only.
2019 · Paper 2 Q11 Using percentages
A sum of \65\,000isdepositedataninterestrateof is deposited at an interest rate of 7\%perannumfor per annum for 8$ years, compounded quarterly. Find the amount correct to the nearest dollar.
A \101\,400$.
B \111\,682$.
C \113\,244$.
D \113\,609$.
2019 · Paper 2 Q12 Rates, ratios and proportions
The costs of tea of brand A and brand B are \140/\text{kg}and and \315/kg315/\text{kg} respectively. If xx kg of tea of brand A and yy kg of tea of brand B are mixed so that the cost of the mixture is \210/\text{kg},then, then x:y=$
A 2:32:3.
B 3:23:2.
C 4:94:9.
D 9:49:4.
2019 · Paper 2 Q13 Variations
It is given that zz varies directly as the square of xx and inversely as the square root of yy. If xx is decreased by 40%40\% and yy is increased by 44%44\%, then zz
A is decreased by 70%70\%.
B is increased by 70%70\%.
C is decreased by 76%76\%.
D is increased by 76%76\%.
2019 · Paper 2 Q14 Arithmetic and geometric sequences and their summations
In the figure, the 1st pattern consists of 6 dots. For any positive integer nn, the (n+1)(n+1)th pattern is formed by adding 4 dots to the nnth pattern. Find the number of dots in the 9th pattern.
Figure
2019 · Paper 2 Q15 Mensuration
The base of a solid right pyramid is a square of side 18 cm18\text{ cm}. If the height of the pyramid is 12 cm12\text{ cm}, then the total surface area of the pyramid is
A 432 cm2432\text{ cm}^{2}.
B 540 cm2540\text{ cm}^{2}.
C 756 cm2756\text{ cm}^{2}.
D 864 cm2864\text{ cm}^{2}.
2019 · Paper 2 Q16 Mensuration
In the figure, ABCDABCD is a parallelogram and AEFGAEFG is a square. It is given that BE:EF:FC=2:7:3BE:EF:FC = 2:7:3. BDBD cuts AEAE and FGFG at the points XX and YY respectively. If the area of ΔABX\Delta ABX is 24 cm224\text{ cm}^{2}, then the area of the quadrilateral CDYFCDYF is
Figure
A 54 cm254\text{ cm}^{2}
B 77 cm277\text{ cm}^{2}
C 81 cm281\text{ cm}^{2}
D 87 cm287\text{ cm}^{2}
2019 · Paper 2 Q17 Angles and parallel lines
In the figure, ABCABC and ADEADE are straight lines. It is given that AB=BDAB = BD and BC=CDBC = CD. If CDE=66\angle CDE = 66^{\circ}, then ACD=\angle ACD =
Figure
A 2828^{\circ}
B 3333^{\circ}
C 3636^{\circ}
D 3838^{\circ}
2019 · Paper 2 Q18 Similar triangles
In the figure, ABCABC is an isosceles triangle with AB=ACAB = AC. DD and EE are points lying on ABAB such that AD=DE=2EBAD = DE = 2EB while FF is a point lying on ACAC such that DF//ECDF // EC. If ADF=90\angle ADF = 90^{\circ} and CE=60CE = 60 cm, then EF=EF =
Figure
A 40 cm40\text{ cm}.
B 45 cm45\text{ cm}.
C 48 cm48\text{ cm}.
D 50 cm50\text{ cm}.
2019 · Paper 2 Q19 Mensuration
In the figure, ABCDABCD is a trapezium with AB//DCAB//DC and ABD=90\angle ABD=90^{\circ}. If AB=18cmAB=18\text{cm}, BC=26cmBC=26\text{cm} and AD=30cmAD=30\text{cm}, find the area of the trapezium ABCDABCD.
Figure
A 336 cm2336\ cm^{2}
B 400 cm2400\ cm^{2}
C 504 cm2504\ cm^{2}
D 552 cm2552\ cm^{2}
2019 · Paper 2 Q20 Quadrilaterals
In the figure, ABCDABCD is a rhombus. ABEABE and BCFBCF are straight lines such that BE=EFBE = EF. If BEF=56\angle BEF = 56^{\circ}, then BDC=\angle BDC =
Figure
A 4848^{\circ}
B 5656^{\circ}
C 5959^{\circ}
D 6262^{\circ}
2019 · Paper 2 Q21 Basic properties of circles
In the figure, O is the centre of the semi-circle ABCDABCD. If AC=BDAC = BD and COD=48\angle COD = 48^{\circ}, then ABD=\angle ABD =
Figure
A 3131^{\circ}
B 3333^{\circ}
C 4242^{\circ}
D 4848^{\circ}
2019 · Paper 2 Q22 Trigonometry
In the figure, ABCDABCD is a rectangle. EE is a point lying on ADAD. Find CEAC\frac{CE}{AC}
Figure
A sinαsinβ\frac{\sin\alpha}{\sin\beta}
B cosαcosβ\frac{\cos\alpha}{\cos\beta}
C sinαsinβ\sin\alpha\sin\beta
D cosαcosβ\cos\alpha\cos\beta
2019 · Paper 2 Q23 Equations of straight lines
In the figure, the equation of the straight line LL is ax+by+15=0ax + by + 15 = 0. Which of the following are true?

I. a>ba>b

II. a>3a>-3

III. b>5b>-5
Figure
A I and II only
B I and III only
C II and III only
D I, II and III
2019 · Paper 2 Q24 Equations of straight lines
Find the constant kk such that the straight lines 3x+2y+k=03x + 2y + k = 0 and kx+12y6=0kx + 12y - 6 = 0 are perpendicular to each other.
A 8-8
B 4-4
C 44
D 88
2019 · Paper 2 Q25 Rectangular coordinate system
The coordinates of the point AA are (5,2)(-5,-2) . AA is translated rightwards by 9 units to the point BB . BB is then rotated anticlockwise about the origin through 9090^{\circ} to the point CC . Find the yy-coordinate of CC.
A -4
B -2
C 2
D 4
2019 · Paper 2 Q26 Loci
The equation of the straight line LL is 5x7y14=05x - 7y - 14 = 0. If PP is a moving point in the rectangular coordinate plane such that the perpendicular distance from PP to LL is equal to 3, then the locus of PP is
A a sector.
B a square.
C a parabola.
D a pair of straight lines.
2019 · Paper 2 Q27 Equations of circles
Denote the circle 2x2+2y2+4x12y+15=02x^{2}+2y^{2}+4x-12y+15=0 by CC. Which of the following is/are true?
A I only
B II only
C I and III only
D II and III only
2019 · Paper 2 Q28 More about probability
Two numbers are randomly drawn at the same time from nine balls numbered 1, 2, 3, 4, 5, 6, 7, 8 and 9 respectively. Find the probability that the two numbers drawn are consecutive integers.
A 12\frac{1}{2}
B 14\frac{1}{4}
C 29\frac{2}{9}
D 79\frac{7}{9}
2019 · Paper 2 Q29 Measures of dispersion
Which of the following can be obtained from any box-and-whisker diagram?

I. Range

II. Standard deviation

III. Inter-quartile range
A I and II only
B I and III only
C II and III only
D I, II and III
2019 · Paper 2 Q30 Measures of central tendency
The table below shows the distribution of the numbers of merits obtained by some students in a year.

[Table]
A The mode of the distribution is 3636.
B The median of the distribution is 88.
C The lower quartile of the distribution is 66.
D The upper quartile of the distribution is 1010.
2019 · Paper 2 Q31 Exponential and logarithmic functions
It is given that log9y\log_{9} y is a linear function of log3x\log_{3} x. The intercepts on the vertical axis and on the horizontal axis of the graph of the linear function are 77 and 88 respectively. Which of the following must be true?
A x4y7=356x^{4}y^{7}=3^{56}
B x7y4=356x^{7}y^{4}=3^{56}
C x7y8=356x^{7}y^{8}=3^{56}
D x8y7=356x^{8}y^{7}=3^{56}
2019 · Paper 2 Q32 Exponential and logarithmic functions
If 33logx2+7=22logx+1\frac{3}{3\log x-2}+7=\frac{2}{2\log x+1}, then log1x=\log\frac{1}{x}=
A 3-3 or 22.
B 2-2 or 33.
C 13\frac{-1}{3} or 12\frac{1}{2}.
D 12\frac{-1}{2} or 13\frac{1}{3}.