If you would like to know the rate at which she was travelling, you can calculate this using the following steps:
300 miles ... 4.5 hours
x miles = ? ... 1 hour
300 * 1 = 4.5 * x
300 = 4.5 * x
x = 300 / 4.5
x = 200 / 3
x = 66.67 miles per hour
Janet was travelling at the rate 66.67 miles per hour.
