Choice E
$$\frac{4}{y}=0.4$$ $$\Rightarrow \frac{4}{y}\times y=0.4\times y$$ $$\Rightarrow 4=0.4y$$ $$\Rightarrow y=10$$
Choice B
$$T=\pi r^{2}+\pi rs$$ $$T=\pi 3^{2}+\pi \times3\times5$$ $$=9\pi+15\pi$$ $$=24\pi$$
Choice B
$$35=5\cdot7$$ $$28=2\cdot2\cdot7$$ $$8=2\cdot2\cdot2$$ $$2\cdot2\cdot2\cdot5\cdot7=280$$
Choice F
$$f(9)=6$$ $$f(12)=8$$ $$F.\ f(x)=\frac{2}{3}n$$ $$f(9)=\frac{2}{3}\times9=6$$ $$f(12)=\frac{2}{3}\times12=8$$
Choice E
$$4000+9000+5000+3000=21000$$ $$45000-21000=24000$$ $$\frac{24000}{45000}=\frac{8}{15}=0.53333...$$
$$(2x-10)+y=180 \Rightarrow 2x+y=190$$ $$(x+25)+(2x+10)+(3x-25)+(2x-10)=360$$ $$\Rightarrow …
Choice D
$$7-2=5$$ $$9-4=5$$ $$8-0=8$$ $$5\times8=40$$
Choice G
$$\tan C=\frac{8}{15}$$
Choice B
$$3a-5b=22---(1)$$ $$a+3b=-2---(2)$$ $$(2)\times3-(1)$$ $$\Rightarrow (3a+9b)-(3a-5b)=(-2)\times3-22$$ …
Choice F
$$3r+4p+50=545$$ $$\Rightarrow 3r+4p=495$$
Choice C
$$1st\ rectangle:\ 1\times2+4\times2=10$$ $$2nd\ rectangle:\ …
Choice F
$$2x^{3}+x^{2}-6x$$ $$=x(2x^{2}+x-6)$$ $$=x(2x-3)(x+2)$$
Choice E
$$P(Not\ blue)$$ $$=1-P(Blue)$$ $$=1-\frac{3}{1+2+3+4}$$ $$=1-\frac{3}{10}$$ …
Choice J
$$3x+1=5x-9$$ $$\Rightarrow 2x=10$$ $$\Rightarrow x=5$$ …
Choice C
$$\cos L=\frac{a}{c}=\frac{7}{16}$$ $$\sin N=\frac{a}{c}=\frac{7}{16}$$
Choice K
$$(3.5+0.25n)(2500-100n)$$
Choice B
$$2\pi r=20$$ $$r=\frac{20}{2\pi}=\frac{10}{\pi}$$
Choice K
$$30°:60°:90°$$ $$\Rightarrow 1:\sqrt{3}:2$$ $$?=500\times\sqrt{3}=500\sqrt{3}$$
Choice C
$$45°:45°:90°$$ $$\Rightarrow 1:1:\sqrt{2}$$ $$\overline{AC}=5\times\sqrt{2}=5\sqrt{2}$$
Choice G
$$1\times4=4$$
Choice D
$$450°=90°\times5$$
Choice J
Choice C
$$\sqrt[3]{3x-9}+10=13$$ $$\Rightarrow \sqrt[3]{3x-9}=3$$ $$\Rightarrow (\sqrt[3]{3x-9})^{3}=3^{3}$$ …
Choice J
$$=$2000(1+\frac{0.06}{12})^{120}$$
Choice A
$$2\div7$$ $$=0.285714285714...$$ $$=0.\overline{285714}$$
Choice K
$$\frac{60+65+70+75+80\times2+85\times3+90\times2+95\times4+100\times5}{20}$$ $$=\frac{60+65+70+75+160+255+180+380+500}{20}$$ $$=\frac{1475}{20}$$ $$=87.25$$
$$P=\frac{64G}{S}$$ $$\Rightarrow G=\frac{P\times S}{64}$$ $$\Rightarrow …
Choice K
x quarters,
x+5 dimes,
x+1 …
$$(3,9)\rightarrow(1,3)$$ $$(3k,9k)=(1,3)$$ $$k=\frac{1}{3}$$ $$(9,24)\Rightarrow(9\times\frac{1}{3},24\frac{1}{3})=(3,8)$$
Choice F
$$5^{2}+8^{2}=x^{2}=89$$ $$\Rightarrow x=\sqrt{89}\approx 9.43$$ $$9.43\times2=18.86$$
Choice E
$$x-20 \Rightarrow x+20$$ $$(x+20)-(x-20)=+40$$ $$$40\ …
Choice F
The range of temperatures is …
Choice A
$$x+3=0$$ $$\Rightarrow x=-3$$
Choice G
$$Circle\ area=\pi r^{2}$$ $$\pi \times …
Choice D
$$\frac{3^{x}3^{4}}{(3^{4})^{5}}=\frac{1}{9}$$ $$\Rightarrow \frac{3^{x+4}}{3^{4\times5}}=\frac{1}{9}$$ $$\Rightarrow \frac{3^{x+4}}{3^{20}}=\frac{1}{9}=3^{-2}$$ …
Choice J
All real numbers except 7.
Choice D
By the Law of Sines, …
Choice G
$$F.\ f(x) > 0 \Rightarrow |f(x)| …
Choice D
To minimize 2/(y-x),
we simply …
Choice F
$$\Rightarrow (-r,s)$$
Choice E
$$=\begin{bmatrix}2 & -5 \\-3 & …
Choice G
$$\overline{AE}=\overline{BE}$$ $$\overline{AG}=\overline{GE}$$ $$\Rightarrow \overline{EF'}:\overline{GH'}$$ $$=\overline{BE}:\overline{BG}$$ …
Choice D
$$ab\gt 0,$$ $$(-)(-)\gt 0,$$ $$(+)(+)\gt …
Choice G
B is between D and …