AMC8 2001

AMC8 2001 · Q5

AMC8 2001 · Q5. It mainly tests Rates (speed), Rounding & estimation.

On a dark and stormy night Snoopy suddenly saw a flash of lightning. Ten seconds later he heard the sound of thunder. The speed of sound is 1088 feet per second and one mile is 5280 feet. Estimate, to the nearest half-mile, how far Snoopy was from the flash of lightning.

在一个漆黑暴风雨的夜晚，史努比突然看到一道闪电。10秒后他听到了雷声。声速是1088英尺每秒，1英里是5280英尺。估计到最近的半英里，史努比距离闪电有多远。

(A) 1 1

(B) 1 1/2 $1\frac{1}{2}$

(D) 2 1/2 $2\frac{1}{2}$

(E) 3 3

Answer

Correct choice: (C)

正确答案：（C）

Solution

Use the formula $d = rt$ (distance equals rate times time): 1088 feet per second $\times 10$ seconds = 10880 feet, which is just 320 feet more than two miles. Therefore, Snoopy is just about two miles from the flash of lightning.

使用公式 $d = rt$（距离等于速率乘时间）：1088英尺每秒 $\times 10$ 秒 = 10880英尺，这刚好比两英里多320英尺。因此，史努比距离闪电大约两英里。

Topics