9514 1404 393
Answer:
1 17/33 hours, about 1.52 hours
Explanation:
The distance between the trucks is increasing at the rate of 60+39 = 99 miles each hour. Then the time to get to a separation distance of 150 miles is ...
(150 mi)/(99 mi/h) = (150/99) h = 1 17/33 h
The trucks will be 150 miles apart after ...
1 17/33 hours, about 1 hour 30 min 55 seconds.