Sam drove for 2hr for 45mph. He has the same distance remaining. How fast should he drive to make his average speed 60mph
To find out how fast Sam should drive to make his average speed 60 mph, we can use the formula for average speed:
Average Speed = Total Distance / Total Time
Since Sam has already driven for 2 hours at 45 mph, he has covered a distance of 2 hours * 45 mph = 90 miles.
Let the remaining distance be x miles. Since the total distance remains the same, the total distance is 90 miles + x miles.
To make his average speed 60 mph, the total time for the entire journey should be (90 miles + x miles) / 60 mph.
We can now set up the equation:
2 hours + x miles / Speed = (90 miles + x miles) / 60 mph
2 + x / 45 = (90 + x) / 60
Multiplying both sides by 45 * 60 to get rid of the denominators:
60(2 + x) = 45(90 + x)
Simplifying:
120 + 60x = 4050 + 45x
15x = 3930
x = 262
Therefore, Sam should drive at a speed of 262 mph to make his average speed 60 mph.