My friend sets out walking at a speed of 3 miles per hour. I set out behind her \(8\) minutes later at 4 miles per hour. For how many minutes will my friend have been walking when I catch up to her?

Let her time in hours==T

3T =4[T + 8/60], solve for T

T ==8/15 x 60 ==32 minutes - she was walking when you caught up.

32 - 8==24 minutes that you walked.

The above line should read:

3T =4[T - 8/60], solve for T