In a science experiment, the temperature of a substance is changed from 42 °F to - 54 °F at an average rate of - 12 degrees per hour. Over how many hours does the change take place?

A 8 hours B

1

8

hour

C - 8 hours D 1 hour

Remark

There are a couple of ways to do this. The easiest is to take the number of degrees between 42 and - 54 and divide by 12.

Method

the number of degrees is abs (42) + abs (-54) = 42 + 54 = 96

Now divide by 12

Hours = 96 / 12 = 8 hours. I think the answer is A.

A. 8 hours because hours can't be negative they go only foward