If she wants to bike 220 km , how long (in hours) must she ride? a cyclist rides at an average speed of 25 miles per hour.

The velocity is a vector quantity (has magnitude and direction), it is calculated by dividing the distance by the time taken to cover the given distance,
In this case the distance is 220 km while the speed is 25 miles per hour
to calculate time taken we divide the distance by the speed.
First we convert the distance into miles , 1 mile = 1.6098 km, therefore 220 km is equivalent to 136.702 miles.
time taken = 136.702 miles ÷ 25 =5.46808 hours
thus, the time taken 5.468 hours