Question 668521
The bus is 20 miles from town and is travelling at 60 mph.
The car is 0 miles from town and is travelling at 70 mph.

Let t be the number of hours one travels.

Then we have that the number of miles away from town for the bus is 20 + 60t

Similarly, we have that the number of miles away from town for the car is 70t.

20 + 60t = 70t

20 = 10t

t = 2 hours

To check:

in 2 hours each vehicle will be exactly 140 miles away from town as 60*2 + 20 = 140 and 70 * 2 = 140