Problem Solving

LUANDATO wrote:At a certain carpet factory, if carpeting of width 10 feet is moving continuously through a dryer at a constant speed of 2160 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

If the area of the carpet is 1 square foot, then the length of the carpet must be 1/10 foot since since the width is 10 feet. Therefore, we need to determine the number of seconds for the carpet of length 1/10 foot to pass through a dryer at a constant speed of 2160 feet per hour. Let's determine the speed in feet per second:

2160 ft / 1 hr = 2160 ft / 3600 sec = 36 ft / 60 sec = 3 ft / 5 sec

Now we can create a proportion where x = the number of seconds for the carpet of length 1/10 foot to pass through the dryer:

(1/10)/x = 3/5

3x = 1/2

x = 1/6

Answer: A