Help please Algebra homework

Question

Two trains leave stations 420 miles apart the same time and travel toward each other. One train travels at 80 mph while the other travels at 70 mph. How long will it take for the trains to meet

Answer 1

What parameter is equal in this problem? Yes, time.

Distance/rate = time

Fast train travels F miles and slow train travels S miles and F+S=420.

F/80 = S/70 => F = 8S/7

Substitute

(8S/7)+S = 420

Clear fractions by multiplying by 7, then collect terms and solve the equation for S.

Then time to meeting is the value of S divided by 70.