Question 76998
Martina leaves home at 9 A.M., bicycling at a rate of 24 mi/h. Two hours later,
 John leaves, driving at the rate of 48 mi/h. At what time will John catch up
 with Martina?
:
We know when J catches up with M, they will have traveled the same distance;
 we can make a simple equation from that fact:
:
let t = the time M on the road when John catches up
Then (t-2) = time J is on the road
:
Distance = speed * time:J
J's dist = M's dist 
48(t-2) = 24t
48t - 96 = 24t
48t - 24t = + 96
24t = 96
t = 96/24
t = 4 hrs from 9 am is 1 pm
:
:
Check using dist:
M: 4*24 = 96
J: 2*48 = 96