If you drive for 2 hours at 80 mph, how fast must you drive during the next hour in order to have an average speed of 75 mph?
75 * 3 = 225
225 - 160 = 65 mph
To find out how fast you must drive during the next hour in order to have an average speed of 75 mph, we can use the concept of average speed.
Average speed is given by the total distance traveled divided by the total time taken.
In this case, you have driven for 2 hours at a speed of 80 mph, so you have covered a distance of 2 * 80 = 160 miles.
To find how fast you must drive during the next hour, let's denote the speed during the next hour as x mph.
During the next hour, you will cover a distance of x miles.
Therefore, your total distance covered will be 160 miles + x miles.
The total time taken will be 2 hours + 1 hour = 3 hours.
Now, we can use the formula for average speed to set up an equation:
Average speed = total distance / total time
75 mph = (160 miles + x miles) / 3 hours
To solve for x, let's multiply both sides of the equation by 3:
75 mph * 3 hours = 160 miles + x miles
225 miles = 160 miles + x miles
Subtracting 160 miles from both sides, we get:
225 miles - 160 miles = x miles
65 miles = x miles
Therefore, in order to have an average speed of 75 mph, you must drive at a speed of 65 mph during the next hour.