Question

Greg drove at a constant speed in a rainstorm for 282 miles. He took a break, and the rain stopped He then drove 250 mies at a spoed that was 3 miles per hour faster than his previous speed. If he drove for 11 hours, find the car's speed for

each part of the trip
The rate of the car in the rain was mph.

Answer 1

9514 1404 393

Answer:

• 47 mph in the rain
• 50 mph later

Explanation:

The speed during the first part of the trip can be represented by x. Then the speed during the second part is x+3 and the total time is ...

time = distance/speed

11 = 282/x +250/(x+3)

11(x)(x+3) = 282(x +3) +250(x) . . . . multiply by x(x+3)

11x^2 -499x -846 = 0 . . . . . . . put in standard form

(11x +18)(x -47) = 0 . . . . . . . factor

x = 47 . . . . . positive solution (makes x-47=0)

The rate of the car in the rain was 47 mph. The rate of the car after the break was 50 mph.