Question 578387

When traveling in opposite directions, you can effectively add their speeds(velocities):

C1= 3mph
C2= 4mph

Aggregate speed = 3+4= 7mph

d=rt

16.8 = 7t

t = 16.8/7 = 2.4 hours

CHECK

3(2.4) + 4(2.4) = 16.8 √