The speed at which the distance is covered by the two vehicles is the sum of their speeds:
... (truck speed) + 1.5×(truck speed) = 2.5×(truck speed)
The time required to cover the distance is inversely proportional to speed, so is
... (2.5 hours)/2.5 = 1.0 hours
It takes 1.0 hours for the vehicles to meet.
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The speed of the truck is (145 mi)/(2.5 h) = 58 mi/h
The speed of the car is 1.5 × 58 mi/h = 87 mi/h.
The speed at which they move toward each other is
... 58 mi/h + 87 mi/h = 145 mi/h
So, the time it takes to cover 145 miles is
... (145 mi)/(145 mi/h) = 1.0 h