Question

Carmen rides her bicycle at a constant rate to the market. When she rides her bicycle back home along the same route, she bikes at three-quarters the rate she biked to the market. At any given time, t, the distance biked can be calculated using the formula d = rt, where d represents distance and r represents rate. If the trip home takes 12 minutes longer than the trip to the market, how many minutes does it take Carmen to bike home?

Answer 1

distance = d

rt = (3/4 r)(t+12)
rt = 3/4 rt + 9r
1/4 rt = 9r
t = 36

So, it takes 36+12=48 minutes to bike home