A truck leaves going 45 mph. One hour later a car going 60 mph leaves in same direction. How long will it take for the car to catch the truck.
In 1 hour, the 1st truck has gone 45 miles.
The 2nd truck gains on it at 15 mph (60 - 45)
45/15 = 3 hours
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That's 3 hours after the car leaves, 4 hours after the truck has left.
6 hours
To find out how long it will take for the car to catch the truck, we can use the concept of relative motion.
Let's assume that the time taken by the car to catch the truck is "t" hours.
In the one hour that the car is delayed, the truck has already covered 45 miles (since it is traveling at a constant speed of 45 mph), because distance is equal to speed multiplied by time.
Now, when the car starts, it is initially 45 miles behind the truck.
Both the truck and the car are traveling in the same direction, so the relative speed between them is the difference in their speeds, which is 60 mph - 45 mph = 15 mph.
Therefore, for the car to catch up with the truck, it needs to cover a distance of 45 miles (which is the initial distance between them), at a relative speed of 15 mph.
Using the formula distance = speed x time, we can write the equation as:
45 miles = 15 mph x t hours
To solve for t, divide both sides of the equation by 15 mph:
t = 45 miles / 15 mph
Simplifying the equation, we get:
t = 3 hours
Therefore, it will take the car 3 hours to catch up with the truck.