Two cars are 30 miles apart and moving toward each other on the same highway. One car is going 10 miles per hour faster than the other. How fast is each of the cars going if they pass each other 15 minutes later?

Answer 1

speed of slower car --- x mph
speed of faster car ---- x+10

after 1 5minutes or 1/4 hour,

(1/4)x + (1/4)(x+10) = 30
x + x+10 = 300

carry on