Problema Solution

Luis Nunez begins walking at a rate of 2 mph.Forty-five minutes after he​ leaves, his​ wife, Kristin, realizes that Luis has forgotten his wallet. Kristin gets on her bicycle and begins riding at a rate of 12 mph along the same path that Luis took. how long will it take for Kristin to catch luis?

Answer provided by our tutors

Let

v1 = 2 mph the speed of Luis Nunez
v2 = 12 mph the speed of Kristin
t = the time of Luis Nunez travel
t - 0.75 = the time of Kristin's travel (since 45 min = 45/60 hours = 0.75 hours)

Since distance = speed*time and they both pass the same distance we have:

t*2 = (t - 0.75)*12

by solving we find

t = 0.9 hours

t = 0.9*60 = 54 min

t - 0.75 = 54 - 45 min = 9 min

Kristin will catch up on Luis after 9 minutes.