Answer:
1 1/2 hours
Explanation:
In one hour, the distance between them is reduced by 7+5 = 12 miles. At that rate, the 18 mile distance between them will be reduced to zero in ...
time = distance/speed
time = (18 mi)/(12 mi/h) = 3/2 h
It will take 1 1/2 hours until Mort and George meet.