Question

"Ashley and Beth drove from city A to city B in exactly 5 hours, not taking any rest stops. Ashley drive up to the area located half way between the two cities at the average speed of 40 miles per hour and then Beth drove the other half at an average speed of 60 miles per hour. How many hours did Beth drive on their trip?"

Answer 1

Time taken by Beth = 2 hours

Explanation:

Given:

Average speed of Ashley = 40 miles per hour

Average speed of Beth = 60 miles per hour

Total time taken = 5 hours

Distance covered by Ashley = Distance covered by Beth

Find:

Total time taken by Beth

Computation:

Assume, Distance covered by Beth = x

So, Distance covered by Ashley = x

Time taken by Beth = t

Time taken by Ashley = 5 - t

So,

Distance covered by Ashley = Average speed of Ashley × Time taken by Ashley

x = 40 × (5 - t)

x = 200 - 40t................Eq1

Distance covered by Beth = Average speed of Beth × Time taken by Beth

x = 60 × t................Eq2

From Eq2 - Eq1

100 t = 200

t = 2 hours

Time taken by Beth = 2 hours