AMC10 2010 B

AMC10 2010 B · Q2

AMC10 2010 B · Q2. It mainly tests Percent, Averages (mean).

Makayla attended two meetings during her 9-hour work day. The first meeting took 45 minutes and the second meeting took twice as long. What percent of her work day was spent attending meetings?

Makayla 在她的 9 小时工作日中参加了两个会议。第一个会议用了 45 分钟，第二个会议用了两倍的时间。她工作日中参加会议所占的百分比是多少？

(A) 15 15

(B) 20 20

(D) 30 30

(E) 35 35

Answer

Correct choice: (C)

正确答案：（C）

Solution

Answer (C): Makayla spent $45 + 2 \cdot 45 = 135$ minutes, or $\frac{135}{60} = \frac{9}{4}$ hours in meetings. Hence she spent $100 \cdot \frac{9/4}{9} = 25$ percent of her time in meetings.

答案（C）：Makayla 花了 $45 + 2 \cdot 45 = 135$ 分钟，或者说在会议中用了 $\frac{135}{60} = \frac{9}{4}$ 小时。因此她在会议中花费的时间占比为 $100 \cdot \frac{9/4}{9} = 25\%$。

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