AMC10 2004 B

AMC10 2004 B · Q3

AMC10 2004 B · Q3. It mainly tests Exponents & radicals, Interest / growth (simple).

At each basketball practice last week, Jenny made twice as many free throws as she made at the previous practice. At her fifth practice she made 48 free throws. How many free throws did she make at the first practice?

上周每次篮球练习，Jenny 罚中的罚球数是前一次的两倍。第五次练习她罚中了 48 个罚球。她第一次练习罚中了多少个罚球？

(A) 3 3

(B) 6 6

(D) 12 12

(E) 15 15

Answer

Correct choice: (A)

正确答案：（A）

Solution

At Jenny’s fourth practice she made $\frac{1}{2}(48) = 24$ free throws. At her third practice she made 12, at her second practice she made 6, and at her first practice she made 3.

Jenny 第四次练习罚中了 $\frac{1}{2}(48) = 24$ 个罚球。第三次练习罚中 12 个，第二次练习罚中 6 个，第一次练习罚中 3 个。

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