# 2018 April(A09) Math Question 1

Choice A

$$slope = \frac{3-(-6)}{5-(-2)}>0$$

# 2018 April(A09) Math Question 2

Choice J

(3 - 4i) + (5 + 3i) = 8 - I

# 2018 April(A09) Math Question 3

Choice C

$$\frac{630}{x}=\frac{2}{7}$$ $$x=\frac{630\times7}{2}=2205$$

# 2018 April(A09) Math Question 4

Choice K

x = 40 + (180-150) = 70

# 2018 April(A09) Math Question 5

Choice C

$$p=\frac{4\times4}{6\times13}\approx 0.21$$

# 2018 April(A09) Math Question 6

Choice H

$$9x-y-5=0 \\$$ $$\Rightarrow 9x-5=y \\$$ $$\Rightarrow y=9x-5$$

# 2018 April(A09) Math Question 7

Choice A

$$XY=5k\\$$ $$YZ=9k \\$$ $$\Rightarrow XZ=14k\\$$ $$\Rightarrow \frac{XY}{XZ}=\frac{5k}{9k}=\frac{5}{9}$$

# 2018 April(A09) Math Question 8

Choice G

$$2x+4\geq -8 \\$$ $$\Rightarrow 2x\geq -8-4 \\$$ $$\Rightarrow x\geq \frac{-8-4}{2}\\$$ $$\Rightarrow x\geq -6$$

# 2018 April(A09) Math Question 9

Choice E

$$(a^3)^{21}=a^{3\times21}=a^{63}$$

# 2018 April(A09) Math Question 10

Choice G

$$f(-3)=3(-3)^2+7(-3)-8=-2$$

# 2018 April(A09) Math Question 11

Choice D

$$2a+(a+3)=93\\$$ $$a=30\\$$ $$a+3=33$$

# 2018 April(A09) Math Question 12

Choice G

$$a_1=10 \\$$ $$d=2 \\$$ $$a_n=10+2(n-1)=2n+8 \\$$ $$S_n=\frac {a_1+a_n}{2}\cdot n=\frac {10+2n+8}{2}\cdot n=220 \\$$ $$n=11$$

# 2018 April(A09) Math Question 13

Choice B

$$\frac {9+x}{2}=3 \\$$ $$\frac {-11+y}{2}=-7 \\$$ $$\Rightarrow x=-3 ,\ y=-3$$

# 2018 April(A09) Math Question 14

Choice J

$$t+v=200\\$$ $$10t+6v=1400\\$$ $$\Rightarrow t=50,\ v=150$$

# 2018 April(A09) Math Question 15

Choice E

$$10\% \times 1800+200=380$$

# 2018 April(A09) Math Question 16

Choice K

$$median=250 \\$$ $$mean=\frac {200+250+300+150+275}{5}=235 \\$$ $$\Rightarrow median - mean = 250-235=15$$

# 2018 April(A09) Math Question 17

Choice E

$$Area = \frac{10\times24}{2}=120 \ dm^2$$

# 2018 April(A09) Math Question 18

Choice J

$$Mean = \frac{82+93+68+93+70+x}{7}=85 \\$$ $$\Rightarrow x=91$$

# 2018 April(A09) Math Question 19

Choice A

$$\sin A = \frac{7}{25}$$

# 2018 April(A09) Math Question 20

Choice G

The longer length of the smaller rectangle (S2) = 12-5=7

$$Total\ area = S1+S2=10 \times 5 + 3 \times 7=71$$

# 2018 April(A09) Math Question 21

Choice A

x+(x+3)+(x+5)=26 => x=6

Choice J

# 2018 April(A09) Math Question 27

Choice C

Monday:

The daily amount for …

# 2018 April(A09) Math Question 28

Choice H

To find the roots of …

# 2018 April(A09) Math Question 29

Choice D

$$BC=\sqrt{AB^2+AC^2}=13$$

Total distance of the …

# 2018 April(A09) Math Question 30

Choice G

The number of students NOT …

# 2018 April(A09) Math Question 31

Choice D

$$\sqrt{x}+3=6 \\$$ $$\Rightarrow \sqrt{x}=3 \\$$ …

# 2018 April(A09) Math Question 32

Choice H

$$\sin A = \frac{3}{4}=\frac{BC}{AB}=\frac{12}{AB} \\$$ …

# 2018 April(A09) Math Question 33

Choice A

$$3(\log_2 16)=3(\log_2 2^4)=3(4)=12$$

# 2018 April(A09) Math Question 34

Choice F

F. is apparently true, because …

# 2018 April(A09) Math Question 35

Choice B

Total distance travelled in 1 …

Choice G

Choice J

# 2018 April(A09) Math Question 44

Choice F

The graph of the function …

# 2018 April(A09) Math Question 45

Choice A

Only Choice A satisfies that …

# 2018 April(A09) Math Question 46

Choice H

When x become really large, …

# 2018 April(A09) Math Question 47

Choice B

The probability of drawing a …

# 2018 April(A09) Math Question 48

Choice K

The expression is undefined whenever …

# 2018 April(A09) Math Question 49

Choice E

$$\frac{\frac{2}{5}+\frac{8}{7}}{2}=\frac{27}{35}$$

# 2018 April(A09) Math Question 50

Choice H

$$3^{x^2-x-2}=1=3^0\\$$ $$x^2-x-2=0\\$$ $$(x-2)(x+1)=0\\$$ $$\Rightarrow x=2,-1$$

# 2018 April(A09) Math Question 51

Choice D

The major radius p is …

# 2018 April(A09) Math Question 52

Choice J

$$p=\frac{3+1}{10}=\frac{4}{10}$$

Choice B

Choice K