2014 AMC 10B 第 6 题

Question

Orvin 去商店时带的钱刚好够买

30

个气球。到店后，他发现气球正在促销：按原价买

1

个气球，第二个可减价

\frac{1}{3}

。Orvin 最多可以买多少个气球？

Orvin went to the store with just enough money to buy

30

balloons. When he arrived, he discovered that the store had a special sale on balloons: buy

1

balloon at the regular price and get a second at

\frac{1}{3}

off the regular price. What is the greatest number of balloons Orvin could buy?

33

34

36

38

39

把每个原价气球和一个折扣气球配成一组。

Pair each full-price balloon with its discounted companion

两个气球的促销组合花费等于

\frac53

个原价气球。

A two-balloon sale pair costs

\frac53

regular balloons

每一对气球的价格是一个气球原价的

1+\frac23=\frac53

倍。

因此，带着刚好够买

30

个原价气球的钱，Orvin 可以买

30\cdot\frac65=36

个气球。

所以正确答案是 C。

Each pair of balloons costs

1+\frac23=\frac53

times the regular price of one balloon.

Thus, with the money for

30

regular-price balloons, Orvin can buy

30\cdot\frac65=36

balloons.

Thus, the correct answer is C .

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