SOLUTION: Billy and Kendall each drove to their grandmother’s house from their house. Billy left one hour before Kendall. Billy drove at a rate of 45 mph. Kendall drove at a rate of 60

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Question 1158562: Billy and Kendall each drove to their grandmother’s house from their house. Billy left one
hour before Kendall. Billy drove at a rate of 45 mph. Kendall drove at a rate of 60 mph. How long will it take for Kendall to catch up to Billy?
Found 2 solutions by greenestamps, ikleyn:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


In the hour that Billy drove at 45mph before Kendall started, Billy drove 45 miles.

Once Kendall started driving at 60mph, the rate at which he caught up to Billy was 60-45 = 15mph.

To make up the 45 miles at a rate of 15 miles per hour will take 45/15 = 3 hours.

If you need an algebraic solution....

When Kendall caught up to Billy, Kendall had driven x hours at 60mph and Billy had driven (x+1) hours at 45mph:

60%28x%29+=+45%28x%2B1%29

Solve using basic algebra.

Answer by ikleyn(52786) About Me  (Show Source):
You can put this solution on YOUR website!
.

This problem,  as it is presented in the post,  has  HUGE  deficiency.

The solution is true  ONLY  IF  the distance from the  B&K  house to the grandmother house is  LONG  ENOUGH.

More concretely,  if this distance is longer than  3*60 = 180 miles.

If the distance is shorter,  then the solution  FALLS.

An  ACCURATE  formulation should  SPECIALLY  reserve/negotiate it.