AMC10 2005 B

AMC10 2005 B · Q5

AMC10 2005 B · Q5. It mainly tests Fractions.

Brianna is using part of the money she earned on her weekend job to buy several equally-priced CDs. She used one fifth of her money to buy one third of the CDs. What fraction of her money will she have left after she buys all the CDs?

Brianna用她周末工作赚的部分钱买几张同样价格的CD。她用五分之一的钱买了三分之一的CD。她买完所有CD后，还剩多少比例的钱？

(A) $\frac{1}{5}$ $\frac{1}{5}$

(B) $\frac{1}{3}$ $\frac{1}{3}$

(D) $\frac{3}{5}$ $\frac{3}{5}$

(E) $\frac{4}{5}$ $\frac{4}{5}$

Answer

Correct choice: (C)

正确答案：（C）

Solution

The number of CDs that Brianna will finally buy is three times the number she has already bought. The fraction of her money that will be required for all the purchases is $(3)(\frac{1}{5}) = \frac{3}{5}$. The fraction she will have left is $1 - \frac{3}{5} = \frac{2}{5}$.

Brianna最终买的CD数量是她已买数量的三倍。所有购买所需钱的比例是$(3)(\frac{1}{5}) = \frac{3}{5}$。剩余比例是$1 - \frac{3}{5} = \frac{2}{5}$。

Topics

AR.001 Fractions