Two cars travel at the same speed to different destinations. Car A reaches its destination in 12 minutes. Car B reaches its destination in 18 minutes. Car B travels 4 miles farther than Car A. How fast do the cars travel?

speed of car A =Speed of car B=0.8 miles/minutes.
Step-by-step explanation:
We are given that speed of car A is equal to speed of car B.
Also let car A travels x miles.
and car B travels y miles.
Car A reaches its destination in 17 minutes.
this means that speed of car A is given by: miles/minutes ( since speed is defined as the ratio of distance and time).
Car B reaches its destination in 32 minutes.
This means that the speed of car B is given by: miles/minutes
as speed of both cars are equal this means:
(1)
Also we are given Car B travels 12 miles farther than Car A.
this means
(2)
on using equation (1) and (2) we have:

Hence the speed of car A is 0.8 miles/minutes ( since x/17 is the speed of car A)
Speed of car B=0.8 miles/minutes.