GWD21-6

GWD21-6

At a certain carpet factory, if carpeting is moving continuously through a dryer at a constant rate of 21,600 square feet per hour, how many seconds does it take for an area of 1 square foot of carpeting to move through the dryer?

A  1/6

B  1/3

C  6

D 36

E 60

我选C 但是答案是A  怎么回事呢？

一小时3600秒，21600尺布，一秒钟就6尺。一尺就1/6秒