請教OG(11th)PS-Q216

[roger0628]

If m>0 and x is m percent of y, then, in terms of m, y is what percent of x?

(A) 100m

(B)1/100m

(C)1/m

(D)10/m

(E)10,000/m

看過解答,還是不懂= =
請高手幫忙解惑,謝謝...

[vantreal]

這題慢慢來做.

x is m percent of y
=> x = (m %) x (y) = (m/100) x (y)
(x 用bold face, 免得和乘號混淆)

由上述 x = (m/100) x (y)
現在求y, 那整理一下
y=100 (x) / m ----- (1)
而題目問percentage
所以設 A percent
y = (A %) x (x) = A(x) /100 ------ (2)

(1) + (2)
100 (x) / m = A(x) /100
兩邊分子都有 x 消掉,
100/m = A/ 100
所以 A = 10,000/m

Ans: (E)