Question

It took Ellen 4.5 hours to drive to her​ mother's house on Wednesday morning. On her return trip on Thursday ​night, traffic was​ heavier, so the trip took her 5 hours. Her average speed on Thursday was 4 mph slower than on Wednesday. What was her average speed on Thursday​?

Answer 1

36 mph was her average speed on Thursday

Explanation:

Data:

Wednesday

time= 4.5 hours

rate = x

Thursday

time= 5 hours

rate = 4 mph slower than on Wednesday = x-4

Solution

We know that distance= (rate)(time)

So the distante on Monday is 4.5x and the distance on

Wednesday is 5(x-4)

As we know she drove the same distance so we have that

4.5x=5(x-4)

4.5x=5x-20

4.5x-5x=-20

-.05x=-20

x=40

Hence 40-4=36 mph