Question

The caldwells are moving across the country. Mr Caldwell leaves 3 hours before Mrs Caldwell. If he averages 45 mph and she averages 65 mph, how many hours will it take Mrs Caldwell to catch mr. Caldwell

Answer 1

Answer:

6 hours 45 minutes

Step-by-step explanation:

Let the time taken by Mr Caldwell to reach the same point as Mrs Caldwell =t

Mr Caldwell's Average Speed=45mph

Distance covered by Mr Caldwell = Speed X Time =45t

Mrs Caldwell left 3 hours later, so her time=t-3

Mrs Caldwell's Average Speed=65mph

Distance covered by Mrs Caldwell = Speed X Time =65(t-3)

Since they will be at the same point, it means their distance from starting point is the same, therefore:

45t=65(t-3)

45t=65t-195

65t-45t=195

20t=195

t=9.75 hours

It will take (t-3) hours to catch Mr Caldwell

t-3 = 9.75 - 3 =6.75 hours=6 hours 45 minutes

It will take 6 hours 45 minutes for Mrs Caldwell to catch Mr Caldwell