Question

一辆卡车每 $t$ 秒行驶 $\dfrac{b}{6}$ 英尺。 $3$ 英尺等于一码。这辆卡车在 $3$ 分钟内行驶多少码？

A truck travels $\dfrac{b}{6}$ feet every $t$ seconds. There are $3$ feet in a yard. How many yards does the truck travel in $3$ minutes?

$\dfrac{b}{1080t}$

$\dfrac{30t}{b}$

$\dfrac{30b}{t}$

$\dfrac{10t}{b}$

$\dfrac{10b}{t}$

卡车每 $t$ 秒行驶 $\dfrac{b}{18}$ 码，因为 $3$ 英尺等于一码；所以卡车每秒行驶 $\dfrac{b}{18t}$ 码。

$3$ 分钟为 $180$ 秒，因此行驶 $\dfrac{b}{18t}\cdot 180 = \dfrac {10b}t.$

所以正确答案是 E。

This means it travels $\dfrac{b}{18}$ yards in $t$ seconds since a yard is $3$ feet. Then, in one second, it travels $\dfrac{b}{18t}$ yards.

Therefore, in $3$ minutes which is $180$ seconds, it travels $\dfrac{b}{18t}\cdot 180 = \dfrac {10b}t.$

Thus, the correct answer is E .