# 2014 December(72G) Math Question 1

- Cost

Choice D

$$250,000\times 3\%=7,500$$

# 2014 December(72G) Math Question 2

Choice F

Solving for the equation, we have x = -3 and 4.

# 2014 December(72G) Math Question 3

Choice B

$$\frac{1}{6}\approx0.167$$

# 2014 December(72G) Math Question 4

Choice H

$$2x+1=5\Rightarrow x=2 \\$$ $$\Rightarrow (x+3)^3=(2+3)^3=5^3=125$$

# 2014 December(72G) Math Question 5

Choice B

<1+2-4,-2+3+2>=<-1,3>

# 2014 December(72G) Math Question 6

Choice H

$$\frac{2}{3}x=6\\$$ $$\Rightarrow 2x=18 \\$$ $$\Rightarrow x=9$$

# 2014 December(72G) Math Question 7

Choice B

$$\frac{-7-11+15+23+45+23+2}{7}=13°C$$

# 2014 December(72G) Math Question 8

Choice K

$$(a+c)>(b+c) \\$$ $$\Rightarrow a>b$$

# 2014 December(72G) Math Question 9

Choice C

$$7y=-2x-12 \\$$ $$\Rightarrow y=-\frac{2}{7}x-\frac{12}{7}$$

# 2014 December(72G) Math Question 10

Choice K

$$h=\sqrt{4^2+8^2}=\sqrt{80}$$

# 2014 December(72G) Math Question 11

Choice C

Only the equation in C fulfils all sets of d and t in the table.

# 2014 December(72G) Math Question 12

Choice G

$$\frac{30}{24}=\frac{40}{x} \\$$ $$\Rightarrow x=32$$

# 2014 December(72G) Math Question 13

Choice D

$$50\times \frac{3+5}{3+2+5}=40$$

# 2014 December(72G) Math Question 14

Choice F

$$3(a+6b)=c \\$$ $$\Rightarrow a+6b=\frac{c}{3} \\$$ $$\Rightarrow a=\frac{c}{3}-6b$$

# 2014 December(72G) Math Question 15

Choice E

$$\sqrt{2x}=10 \\$$ $$\Rightarrow 2x=100 \\$$ $$\Rightarrow x=50$$

# 2014 December(72G) Math Question 16

Choice H

$$\frac{10^2-10}{2}=45$$

# 2014 December(72G) Math Question 17

Choice A

$$\tan\alpha=\frac{\sin\alpha}{\cos\alpha} \\$$ $$\Rightarrow \cos\alpha=\frac{\sin\alpha}{\tan\alpha}=\frac{\frac{112}{113}}{\frac{112}{15}}=\frac{15}{113}$$

# 2014 December(72G) Math Question 18

Choice H

$$\angle A = \frac{180°-75°}{2}=52.5°$$

# 2014 December(72G) Math Question 19

Choice B

$$150=300(\frac{t+1}{24}) \\$$ $$\Rightarrow t\approx 11$$

# 2014 December(72G) Math Question 20

Choice F

As can be seen from the graph, only (7,2) is 3 cm from (4,2).

# 2014 December(72G) Math Question 21

Choice D

$$\frac{30}{60\times4}\times360°=45°$$

Choice F