Alejandro rode his bike to work at an average rate of 15 miles per hour. to go home, he put his bike on the front rack of the bus and took the bus home along the same route, traveling at an average rate of 22.5 miles per hour. if alejandro’s bike ride to work took 45 minutes, how many hours did the bus ride home take?

a) 0.25 hours

b) 0.3 hours

c) 0.5 hours

d) 0.75 hours