1/2 hour
Step-by-step explanation:
speed = distance/time
distacne = speed × time
d = r ×t
for a speed of 4mph,
d = 4 × t = 4t
for a speed of 6 mph,
d = 6 × t = 6t
since they are going in opposite direction, we add there distance together
4t + 6t = their distance apart
their distance apart = 5 miles
4t + 6t = 5 miles
10t = 5
t = 5/10
t = 1/2 hour
It will take them 1/2 hour before they are 5 miles apart