Problema Solution
The imfamous Mr. X has once again escaped from the central prison. After burrowing under the prison walls, he steals the Warden's bicycle and rides (at the usual rate od 20 mph) the 13 miles to a boat that awaits him on Sunset Beach. twenty minutes after Mr. X departs The Warden discovers his pans and sets out in a squad car the retrive the escapee. If the car cannot drive more than 70 mph will the Warden catch Mr. X before he reaches the boat?
Answer provided by our tutors
let
x = 20 mph the speed of Mr.X
d = 13 miles the distance to Sunset Beach
c = 70 mph the speed of the car
since speed = distance/time => time = distance/speed
the time Mr.X needs to pass d=13 miles is t1 = d/x = 13/20 hours
the time the police car needs to pass d=13 miles is d/c = 13/70 hours
since the car starts to move after 20 min = 20/60 = 1/3 hours we need to compare
t1 = 13/20 and t2 =1/3 + 13/70
t1 = 0.65 h
t2 = 0.519 h
t1 > t2
thus the Warden will catch Mr.X before he reaches the boat.