Carcass wrote:

Phil is making a 40-kilometer canoe trip. If he travels at 30 kilometers per hour for the first 10 kilometers, and then at 15 kilometers per hour for the rest of the trip, how many minutes longer will it take him than if he makes the entire trip at 20 kilometers per hour?

Speed = Dist/Time

First Trip:

10kms | 30kms

|------------|------------------------------|

30kms/hr | 15km/hr

Therefore total time taken in hrs = 10/30 +30/15 = 7/3 hrs = 140 mins

Second Trip:

40kms

|----------------------------------------|

20km/hr

therefore, total time in hrs = 40/20 = 2hrs = 120 mins

Difference = 20 mins

A. 15

B. 20

C. 35

D. 45

E. 50