# 2020 June(C02) Math Question 1

Choice B

$$60=2\times2\times3\times5$$ $$84=2\times2\times3\times7$$ $$126=2\times3\times3\times7$$ $$(64,84,126)=2\times3=6$$

# 2020 June(C02) Math Question 2

Choice J

$$=(4)(3)(n^{7})(n^{5})$$ $$=12(n^{7+5})$$ $$=12(n^{12})$$

# 2020 June(C02) Math Question 3

- Cost

Choice C

$$88\times\frac{3}{4}=66$$ $$(20\times4)-(66\times1.07)$$ $$=80-70.62$$ $$=9.38$$

# 2020 June(C02) Math Question 4

Choice J

$$82\times1+x\times0.5=140$$ $$\Rightarrow 0.5x=140-82=58$$ $$\Rightarrow x=116$$

# 2020 June(C02) Math Question 5

Choice D

$$\because \overline{AB}=\overline{BC}$$ $$\therefore \angle BAC=\angle BCA=38°$$ $$\Rightarrow \angle B=180°-38°-38°=104°$$

# 2020 June(C02) Math Question 6

Choice G

$$(81+84+62+94)\div4=80.25$$

Only one girl ran the race in less time than the average of the 4 running times.

# 2020 June(C02) Math Question 7

Choice D

From 9:00 a.m. to 10:20 a.m., a total of 80 minutes.

$$\frac{18000}{80}=225$$

# 2020 June(C02) Math Question 8

Choice H

$$\Rightarrow (-1+5,3+8)=(4,11)$$

# 2020 June(C02) Math Question 9

Choice B

$$5-\frac{1}{2}-1\frac{3}{4}$$ $$=5-\frac{2}{4}-1\frac{3}{4}$$ $$=2\frac{3}{4}$$

# 2020 June(C02) Math Question 10

Choice G

$$r=-3(4)+2$$ $$r=-12+2$$ $$r=-10$$

# 2020 June(C02) Math Question 11

Choice A

$$f(x)=mx+b$$ $$6=m(8)+b---(1)$$ $$9=m(12)+b---(2)$$ $$(2)-(1)$$ $$\Rightarrow 3=4m$$ $$\Rightarrow m=\frac{3}{4}$$ $$f(x)=\frac{3}{4}x+b$$ $$6=6+b$$ $$b=0$$ $$f(n)=\frac{3}{4}n$$

# 2020 June(C02) Math Question 12

Choice G

$$f(-5)=-4(-5)^{2}=-4(25)=-100$$

# 2020 June(C02) Math Question 13

Choice B

$$=4(-1)^{3}-2(-1)^{2}$$ $$=-4-2$$ $$=-6$$

# 2020 June(C02) Math Question 14

Choice H

$$9\times6+4\times11$$ $$=54+44$$ $$=98$$

# 2020 June(C02) Math Question 15

Choice C

The slope is negative and intersects the Y axis at a position where Y is greater than 0, so the Y axis intercept is positive.

# 2020 June(C02) Math Question 16

Choice G

$$4x+2=-10$$ $$\Rightarrow 4x=-12$$ $$\Rightarrow x=-3$$ …

# 2020 June(C02) Math Question 17

Choice B

According to the picture provided, it can be observed that the maximum value of this function, that is, the maximum value of Y is 3.

# 2020 June(C02) Math Question 18

Choice F

The mean is the average of the numbers.

The Median is the "middle" of a sorted list of numbers.

The mode is the number that is repeated more often than any other.

$$6,7,7,6,8,7,8,10,9$$

Rearrange the 9 scores in order.

$$\rightarrow 6,6,7,7,7,8,8,9,10$$ $$Mean=(6+6+7+7+7+8+8+9+10)\div9=68\div9\approx7.55$$ $$Median=7$$ $$Mode=7$$

After correcting the 9th score to 10.

$$\rightarrow 6,6,7,7,7,8,8,10,10$$ $$Mean=(68+1)\div9\approx7.66$$ $$Median=7$$ $$Mode=7$$

Only the mean is changed.

# 2020 June(C02) Math Question 19

Choice E

Parallel lines have the same slope and will never intersect.

$$y=\frac{2}{3}x+4$$ $$\Rightarrow Slope=\frac{2}{3}$$

Only the E option has the same slope.

# 2020 June(C02) Math Question 20

Choice H

$$\tan \theta=\frac{Opposite}{Adjacent}$$ $$\tan B=\frac{1}{\sqrt{2}}$$

# 2020 June(C02) Math Question 21

Choice E

It's very clear after drawing …

# 2020 June(C02) Math Question 22

Choice J

1 foot is equal to …

# 2020 June(C02) Math Question 23

Choice E

1 foot is equal to …

# 2020 June(C02) Math Question 24

Choice H

$$2^{2}=1^{2}+x^{2}$$ $$\Rightarrow x=\sqrt{3}$$ $$1:\sqrt{3}:2$$

It …

# 2020 June(C02) Math Question 25

Choice E

$$x\times x+(x-2)(x-2)$$ $$=x^{2}+x^{2}-4x+4$$ $$=2x^{2}-4x+4$$

# 2020 June(C02) Math Question 26

Choice H

$$\frac{5}{2}x+\frac{3}{4}y=-\frac{1}{2}$$ $$\Rightarrow 4\times\frac{5}{2}x+4\times\frac{3}{4}y=4\times(-\frac{1}{2})$$ $$\Rightarrow 10x+3y=-2$$ …

# 2020 June(C02) Math Question 27

Choice D

$$0.5+34.2(0.05)$$ $$=0.5+1.71$$ $$=2.21$$

# 2020 June(C02) Math Question 28

Choice F

$$5.75\div0.5=11.5$$

# 2020 June(C02) Math Question 29

Choice D

$$x+y=116---(1)$$ $$0.03x+0.05y=4.34---(2)$$ $$(1)\times5-(2)\times100$$ $$(5x+5y)-(3x+5y)=580-434$$ $$2x=146$$ …

# 2020 June(C02) Math Question 30

Choice J

$$V=\pi r^{2}h$$ $$V=3.14(6)^{2}(5)=565.2$$ $$565.2\times2,205=1,246,266$$

It's …

# 2020 June(C02) Math Question 31

Choice C

$$Children: x$$ $$Adults: y$$ $$x+y=21---(1)$$ …

# 2020 June(C02) Math Question 32

Choice K

$$(\frac{2x^{3}y^{-5}z^{8}}{8x^{-2}y^{6}z^{3}})^{-2}$$ $$=(\frac{2}{8})(\frac{x^{3}y^{-5}z^{8}}{x^{-2}y^{6}z^{3}})^{-2}$$ $$=(\frac{1}{4})(x^{3-(-2)}y^{-5-6}z^{8-3})^{-2}$$ $$=(2^{-2})(x^{5}y^{-11}z^{5})^{-2}$$ $$=(2^{(-2)(-2)})(x^{5(-2)}y^{(-11)(-2)}z^{5(-2)})$$ …

# 2020 June(C02) Math Question 33

Choice D

$$g(-1)=(-1)^{2}-1=1-1=0$$ $$f(g(-1))=f(0)=2(0)+3=3$$

# 2020 June(C02) Math Question 34

Choice J

Choose a pot from the …

# 2020 June(C02) Math Question 35

Choice B

Area of a trapezoid is …

# 2020 June(C02) Math Question 36

Choice H

First calculate the area of …

Choice A

# 2020 June(C02) Math Question 43

Choice D

The Median is the "middle" …

# 2020 June(C02) Math Question 44

Choice F

$$4\times2=8$$ $$8-3=5$$

# 2020 June(C02) Math Question 45

Choice B

$$x-1=x-1$$ $$-(x-1)=x-1$$ $$-x+1=x-1$$ $$\Rightarrow x=1$$ …

# 2020 June(C02) Math Question 46

Choice F

We require that the value …

# 2020 June(C02) Math Question 47

Choice C

$$\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}=1$$ $$\Rightarrow \frac{x^{2}}{5^{2}}+\frac{y^{2}}{3^{2}}=1$$ $$\Rightarrow 9x^{2}+52y^{2}=1\times9\times25$$ …

# 2020 June(C02) Math Question 48

Choice F

$$(-2)^{2}+(-2)b-6=0$$ $$\Rightarrow 4-2b-6=0$$ $$\Rightarrow -2=2b$$ …

# 2020 June(C02) Math Question 49

Choice C

$$\Rightarrow 1:7$$

# 2020 June(C02) Math Question 50

Choice G

$$12\div2=6$$ $$1+2+3=6$$ $$\mid-3\mid+\mid-2\mid+\mid-1\mid+\mid0\mid+\mid1\mid+\mid2\mid+ \mid3\mid$$ $$=3+2+1+0+1+2+3$$ …

# 2020 June(C02) Math Question 51

Choice C

$$f(g(x))$$ $$=\sqrt{(x-3)^{3}}+1$$

If x < 3, you would be taking the square root of a negative number, so x ≥ 3.

# 2020 June(C02) Math Question 52

Choice G

$$(0,0)$$ $$\rightarrow(0+4,0)=(4,0)$$ $$\rightarrow(4,0-1)=(4,-1)$$ $$\rightarrow(4+2,-1)=(6,-1)$$ $$\rightarrow(6,-1-6)=(6,-7)$$ …

# 2020 June(C02) Math Question 53

Choice B

A Rational Number can be …

# 2020 June(C02) Math Question 54

Choice K

Let X be -0.5 and …

# 2020 June(C02) Math Question 55

Choice E

$$8:00\ a.m.\ \rightarrow \sin \theta=\frac{2}{6}$$ …

# 2020 June(C02) Math Question 56

Choice K

$$\frac{2-i}{-3+i}$$ $$=\frac{(2-i)(-3-i)}{(-3+i)(-3-i)}$$ $$=\frac{-6-2i+3i+i^{2}}{(-3)^{2}-(i)^{2}}$$ $$=\frac{-6+i-1}{9-(-1)}$$ $$=\frac{(-7+i)}{10}$$ …

# 2020 June(C02) Math Question 57

Choice E

The sum of the internal …

# 2020 June(C02) Math Question 58

Choice K

The absolute value sign is …

- Cost

Choice D