AMC 8 1997 Problem 8

AMC8 1997 年第 8 题

表达式与运算★★☆☆☆

Walter gets up at 6:30 a.m., catches the school bus at 7:30 a.m., has 6 classes that last 50 minutes each, has 30 minutes for lunch, and has 2 hours additional time at school. He takes the bus home and arrives at 4:00 p.m. How many minutes has he spent on the bus?

Walter 早上 6:30 起床，7:30 赶校车，有 6 节课每节 50 分钟，有 30 分钟午饭时间，还有 2 小时额外在校时间。他乘校车回家，下午 4:00 到家。他在校车上花了多少分钟？

A.30
B.60
C.75
D.90
E.120

正确答案 · Correct Answer

解析 · Solution

Solution 1

There are

\displaystyle 4\frac{1}{2}

hours from 7:30 a.m. to noon, and 4 hours from noon to 4 p.m., meaning Walter was away from home for a total of

\displaystyle 8\frac{1}{2}

hours, or 8.5×60 = 510 minutes.

Tallying up the times he was not on the bus, he has 6×50 = 300 minutes in classes, 30 minutes at lunch, and 2×60 = 120 minutes of "additional time". That is a total of 300 + 30 + 120 = 450 minutes that Walter was away from home, but not on the bus.

Therefore, Walter spent 510 - 450 = 60 minutes on the bus, and the answer is

B

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