A logistics company dispatches a delivery van traveling on a straight highway at a constant speed of mph. Exactly minutes later, a courier is dispatched from the same location to intercept the van, traveling on the same highway at a constant speed of mph. How many hours will it take the courier to catch up to the delivery van after departing?
- A
- B
- Cevap
- D
Cevap
It will take hours for the courier to catch up to the delivery van.
First, the van's head start of 90 minutes must be converted to 1.5 hours. Traveling at 40 mph for 1.5 hours puts the van 60 miles ahead of the starting point. Next, because the vehicles travel in the same direction, their relative speed is the difference between their individual speeds: 60 mph - 40 mph = 20 mph. This means the courier gains 20 miles on the van every hour. Finally, divide the 60-mile gap by the 20 mph relative speed to find the time: 60 / 20 = 3 hours.
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Anahtar Kavram
Relative motion in the same direction requires subtracting the speed of the slower object from the faster object to find the relative rate of closure.
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