On Monday, a bicyclist traveled 38.4 miles in 3 hours. On Tuesday, he traveled the same number of miles, but in half the time. What must have happened to his speed?
A.
His speed decreased by one-third.
B.
His speed doubled.
C.
His speed tripled.
D.
His speed decreased by one-half.
B. His speed doubled.
We can use the formula:
Speed = Distance / Time
On Monday:
Speed = 38.4 miles / 3 hours = 12.8 mph
On Tuesday:
Distance is the same (38.4 miles), but time is half (1.5 hours):
Speed = 38.4 miles / 1.5 hours = 25.6 mph
Therefore, the bicyclist's speed doubled from Monday to Tuesday.