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?
A. 15
B. 20
C. 35
D. 45
E. 50
Total Time taken for covering the distance at 20km/hr for the entire distance = \(\frac{40}{20} = 2 hr = 120 minutes\)
Now for the 1st 10 kms
Time taken for covering the distance at 30 km/hr = \(\frac{10}{30} = \frac{1}{3} hr = 20 minutes\)
Now for the 2nd 30 kms
Time taken for covering the distance at 15 km/hr = \(\frac{30}{15} = 2 hr = 120 minutes\)
So total time taken in this breakup journey = \(120 + 20 = 140 minutes.\)
Therefore extra time taken = \(140 -120 = 20 minutes\)