Question 491200
A police car leaves in pursuit of holdup car 0.5 hours after the latter has left the scene of the crime at 86mi/hr. How fast in mi/hr must the police car go if it is to catch up with the holdup car in one hour?
--------------------
The car is 43 miles away (86*0.5)
To gain on it 43 miles in 1 hour, you have to go 43 mi/hr wrt to car, which is 86+43 mi/hr wrt the Earth.
86 + 43 = 129 mi/hr
---------
wrt = with respect to