Question

A large truck is going down a hill at 60 miles per hour. The driver needs to begin slowing down by shifting the gears. The speed goes down by 10 miles per hour each time he downshifts. Which expression shows his speed after three shifts?

Answer 1

Let, the number of down-shifts(taken by driver) is = x
Expression would be: 60 - 10x

For particular 3 hours, it would be:
⇒60 - 10(3)
⇒60 - 30
⇒30 mph

In short, Final expression would be 60-10(3) mph

Hope this helps!

Answer 2

The answer is D. 69 + ( - 10 x 3 )