# 2019 June(72F) Math Question 1

Choice E

$$\frac{4}{y}=0.4$$ $$\Rightarrow \frac{4}{y}\times y=0.4\times y$$ $$\Rightarrow 4=0.4y$$ $$\Rightarrow y=10$$

# 2019 June(72F) Math Question 2

- Cost

Choice J

$$60\times1.24=74.4$$

# 2019 June(72F) Math Question 3

Choice C

$$10\times40+10\times(1\frac{1}{2})\times7$$ $$=400+105$$ $$=505$$

# 2019 June(72F) Math Question 4

Choice J

$$3x^{9}\cdot 5x^{9}$$ $$=3\times5\times x^{9+9}$$ $$=15x^{18}$$

# 2019 June(72F) Math Question 5

Choice B

$$T=\pi r^{2}+\pi rs$$ $$T=\pi 3^{2}+\pi \times3\times5$$ $$=9\pi+15\pi$$ $$=24\pi$$

# 2019 June(72F) Math Question 6

Choice K

$$180°-45°-65°=70°$$

# 2019 June(72F) Math Question 7

Choice B

$$35=5\cdot7$$ $$28=2\cdot2\cdot7$$ $$8=2\cdot2\cdot2$$ $$2\cdot2\cdot2\cdot5\cdot7=280$$

# 2019 June(72F) Math Question 8

$$x=-2,5$$ $$f(x)=(x-5)(x+2)^{2}$$ $$f(-2)=0$$ $$f(5)=0$$

# 2019 June(72F) Math Question 9

Choice F

$$60\div(3+5+7)=60\div15=4$$ $$4\times7=28$$

# 2019 June(72F) Math Question 10

Choice F

$$f(9)=6$$ $$f(12)=8$$ $$F.\ f(x)=\frac{2}{3}n$$ $$f(9)=\frac{2}{3}\times9=6$$ $$f(12)=\frac{2}{3}\times12=8$$

# 2019 June(72F) Math Question 11

Choice C

$$(\frac{2+8}{2}，\frac{5+11}{2})=(5，8)$$

# 2019 June(72F) Math Question 12

Choice F

$$1\times1\times\frac{1}{9}=\frac{1}{9}$$

# 2019 June(72F) Math Question 13

Choice C

$$=3x^{2}+x^{2}-4x-6x-5-7$$ $$=4x^{2}-10x-12$$

Choice H

22 is even.

22 is not prime.

# 2019 June(72F) Math Question 15

Choice C

$$=\mid-42+32\mid=\mid-10\mid=10$$

# 2019 June(72F) Math Question 16

Choice G

$$11x+6y=3$$ $$y=\frac{-11}{6}x+3$$

# 2019 June(72F) Math Question 17

Choice A

$$g(2,4,3)$$ $$=4\times2\times4-3\times2\times (-3)^{2}$$ $$=32-54=-22$$

# 2019 June(72F) Math Question 18

Choice H

$$x°:360°=5000:45000$$ $$\Rightarrow x=40°$$

# 2019 June(72F) Math Question 19

Choice A

$$4000\div5=800$$

# 2019 June(72F) Math Question 20

$$3000:9000=1:3=\frac{1}{3}$$

# 2019 June(72F) Math Question 21

Choice E

$$4000+9000+5000+3000=21000$$ $$45000-21000=24000$$ $$\frac{24000}{45000}=\frac{8}{15}=0.53333...$$

# 2019 June(72F) Math Question 28

Choice F

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

# 2019 June(72F) Math Question 29

Choice E

$$P(Not\ blue)$$ $$=1-P(Blue)$$ $$=1-\frac{3}{1+2+3+4}$$ $$=1-\frac{3}{10}$$ …

# 2019 June(72F) Math Question 30

Choice J

$$3x+1=5x-9$$ $$\Rightarrow 2x=10$$ $$\Rightarrow x=5$$ …

# 2019 June(72F) Math Question 31

Choice C

$$\cos L=\frac{a}{c}=\frac{7}{16}$$ $$\sin N=\frac{a}{c}=\frac{7}{16}$$

# 2019 June(72F) Math Question 32

Choice K

$$(3.5+0.25n)(2500-100n)$$

# 2019 June(72F) Math Question 33

Choice B

$$2\pi r=20$$ $$r=\frac{20}{2\pi}=\frac{10}{\pi}$$

# 2019 June(72F) Math Question 34

Choice K

$$30°:60°:90°$$ $$\Rightarrow 1:\sqrt{3}:2$$ $$?=500\times\sqrt{3}=500\sqrt{3}$$

# 2019 June(72F) Math Question 35

Choice C

$$45°:45°:90°$$ $$\Rightarrow 1:1:\sqrt{2}$$ $$\overline{AC}=5\times\sqrt{2}=5\sqrt{2}$$

# 2019 June(72F) Math Question 36

Choice G

$$1\times4=4$$

# 2019 June(72F) Math Question 37

Choice D

$$450°=90°\times5$$

Choice J

# 2019 June(72F) Math Question 39

Choice C

$$\sqrt[3]{3x-9}+10=13$$ $$\Rightarrow \sqrt[3]{3x-9}=3$$ $$\Rightarrow (\sqrt[3]{3x-9})^{3}=3^{3}$$ …

# 2019 June(72F) Math Question 40

Choice J

$$=2000(1+\frac{0.06}{12})^{120}$$

# 2019 June(72F) Math Question 41

Choice A

$$2\div7$$ $$=0.285714285714...$$ $$=0.\overline{285714}$$

# 2019 June(72F) Math Question 42

Choice K

$$\frac{60+65+70+75+80\times2+85\times3+90\times2+95\times4+100\times5}{20}$$ $$=\frac{60+65+70+75+160+255+180+380+500}{20}$$ $$=\frac{1475}{20}$$ $$=87.25$$

# 2019 June(72F) Math Question 48

Choice F

The range of temperatures is …

# 2019 June(72F) Math Question 49

Choice A

$$x+3=0$$ $$\Rightarrow x=-3$$

Choice G

# 2019 June(72F) Math Question 55

Choice D

To minimize 2/(y-x),

we simply …

# 2019 June(72F) Math Question 56

Choice F

$$\Rightarrow (-r,s)$$

Choice E

# 2019 June(72F) Math Question 60

Choice G

B is between D and …