Math Problem x2

Question

Robert left the library traveling 4 mph. Then, 4 hours later, Allen left traveling the same direction at 12 mph. How long until Allen catches up with Robert

Answer 1

Distance = rate × time

When Allen leaves, Robert has already traveled 4•4 = 16 miles. When both Allen and Robert have traveled the same distance, then Allen has caught up to Robert.

d_r = 16 + 4t Roberts distance.

d_a = 12t

We want the time when d_r= d_a.

16 + 4t = 12t

8t = 16

t = 16/8 = 2 hours

After two hours, both Allen and Robert have traveled 24 miles.