# 2013 December(71E) Math Question 1

Choice C

$$42:49=\frac{42}{49}$$ $$=\frac{7\times6}{7\times7}=\frac{6}{7}$$

# 2013 December(71E) Math Question 2

Choice F

$$x=6,(6-2)(6-10)=4(-4)=-16=c$$

# 2013 December(71E) Math Question 3

Choice E

$$(50+30+70)4.05=150\times4.05=607.5$$

# 2013 December(71E) Math Question 4

Choice J

$$=5\times3\times p^{6+2}=15p^{8}$$

# 2013 December(71E) Math Question 5

- Cost

Choice D

$$35(1+0.08)=35+2.8=37.8$$

# 2013 December(71E) Math Question 6

Choice J

$$P(Yellow)$$ $$=\frac{9}{11+9+5+n}$$ $$=\frac{9}{25+n}$$

Choice A

# 2013 December(71E) Math Question 8

Choice H

$$303,488,509=3.03\times10^{8}$$

# 2013 December(71E) Math Question 9

Choice D

$$x°+y°=180°$$

# 2013 December(71E) Math Question 10

Choice J

$$\angle BCA=\angle ECF=31°$$ $$\angle BAC=\angle BCA=31°$$ $$\angle ABC=180°-31°-31°=118°$$

# 2013 December(71E) Math Question 11

Choice D

$$(7+\frac{1}{5})\div(1+\frac{1}{10})$$ $$=\frac{36}{5}\times\frac{10}{11}$$ $$=\frac{72}{11}$$ $$=6\frac{6}{11}$$

# 2013 December(71E) Math Question 12

Choice H

$$6\times10=60$$ $$60=2\times2\times3\times5$$

# 2013 December(71E) Math Question 13

Choice C

$$98-50=48$$ $$48\div3=16$$ $$21\div3=7$$ $$16-7=9$$

# 2013 December(71E) Math Question 14

Choice H

$$7\times4+4\times10=28+40=68$$

# 2013 December(71E) Math Question 15

Choice B

$$=\mid-2\mid-\mid-6\mid=2-6=-4$$

# 2013 December(71E) Math Question 16

Choice F

$$96\times\frac{28}{100}=n$$ $$\Rightarrow \frac{28}{100}=\frac{n}{96}$$

# 2013 December(71E) Math Question 17

Choice B

$$8-2=6$$ $$-8-(-6)=-2$$ $$\Rightarrow(2-6,-6-(-2))=(-4,-4)$$

# 2013 December(71E) Math Question 18

Choice K

$$g(-3)=2\times(-3)^{2}-3(-3)$$ $$=2\times9+9$$ $$=27$$

# 2013 December(71E) Math Question 19

Choice A

$$x\lt9,x\gt-1$$

# 2013 December(71E) Math Question 20

Choice K

$$\Rightarrow 5x+10\gt6x-30$$ $$\Rightarrow 40\gt x$$

Choice C

# 2013 December(71E) Math Question 25

Choice A

$$\overline{BC}=\sqrt{15^{2}-9^{2}}=12$$ $$\sin A=\frac{12}{15}=\frac{4}{5}$$

# 2013 December(71E) Math Question 26

Choice F

$$(a-1)(a-1)$$ $$=a^{2}-a-a+1$$ $$=a^{2}-2a+1$$

# 2013 December(71E) Math Question 27

Choice B

$$r=18\div2=9$$ $$2\pi\times9=18\pi$$

# 2013 December(71E) Math Question 28

Choice K

$$x^{2}+2=3$$ $$x^{2}=1$$ $$x=1,-1$$

# 2013 December(71E) Math Question 29

Choice D

$$54\times24=1200$$ $$120\div225=5.3333...$$

# 2013 December(71E) Math Question 30

Choice K

$$(60+34)2=194\times2=188$$

# 2013 December(71E) Math Question 31

Choice B

$$1\ yard = 3\ feet$$ …

# 2013 December(71E) Math Question 32

Choice H

$$\frac{1}{2}\times\frac{2}{6}=\frac{1}{6}$$

Choice C

# 2013 December(71E) Math Question 41

Choice B

$$4:\sqrt{52}=x:\sqrt{13}$$ $$\Rightarrow x=2$$ $$2^{2}+y^{2}=(\sqrt{13})^{2}$$ $$=4+y^{2}=13$$ …

# 2013 December(71E) Math Question 42

Choice J

$$\frac{50\times3+40\times2}{5}$$ $$=\frac{230}{5}$$ $$=46$$

Choice B

# 2013 December(71E) Math Question 44

- FOIL

Choice G

$$(x+3)^{2}-x^{2}$$ $$=x^{2}+3x+3x+9-x^{2}$$ $$=6x+9$$

# 2013 December(71E) Math Question 45

Choice B

$$60°:60°:60°$$ $$=1:1:1$$ $$\overline{AB}=\frac{9}{2}\times\frac{1}{2}=\frac{9}{4}$$

# 2013 December(71E) Math Question 46

Choice K

$$a=\frac{1}{\sqrt{b}}$$ $$(\frac{1}{\sqrt{b}})^{2}\times b=\frac{1}{b}\times b=1$$

Choice A

# 2013 December(71E) Math Question 56

Choice K

Absolute value describes the distance …

# 2013 December(71E) Math Question 57

Choice C

$$3\times15=45$$ $$60-45=15$$ $$5-3=2$$ $$15\div2=7...1$$ $$15-8=7$$

# 2013 December(71E) Math Question 58

Choice J

$$\sin \theta=x$$ $$x^{2}-x=-\frac{1}{4}$$ $$x^{2}-x+\frac{1}{4}=0$$ $$4(x^{2}-x+\frac{1}{4})=0$$ …

# 2013 December(71E) Math Question 59

Choice B

$$y=\frac{4}{3}x-2---(1)$$ $$(1)\times6\Rightarrow 6y=8x-12$$ $$8x-6y=12$$ $$\frac{12}{8}=\frac{3}{2}$$ …

# 2013 December(71E) Math Question 60

Choice H

$$\pi r^{2}=\pi 6^{2}=36\pi$$ $$\frac{32\pi}{36\pi}=\frac{320}{360}$$ $$360-320=40$$ …