Brian is planning a training session for his upcoming triathlon. He ha

In the table below, select the number of miles that Brian can complete running and cycling for a total of exactly 3 hours, assuming that he can switch from one activity to the other instantly.

Running Speed (mph) = R = 10
Cycling Speed (mph) = C = 20
Since he wants to spend more time on Running, lets find out the time in which he can complete the below distances if he cycles them, subsequently we can find the distance which he can complete while running in the remaining time. (while meeting our timing conditions)

15 - If he Cycles for 15 miles then the time taken will be 45 mins. Remaining 2 hours 15 minutes will be spent on Running, during which he will cover a distance of 22.5 miles. But since 22.5 is not an option, 15 miles cannot be the Cycling distance.

20 - If he Cycles for 20 miles then the time taken will be 1 hour. Remaining 2 hours will be spent on Running, during which he will cover a distance of 20 miles. So this is our answer for both activities, since it is also meeting our condition.

30 - If he Cycles for 30 miles then the time taken will be 1 hour 30 minutes. Remaining 1 hours 30 minutes will be spent on Running, during which he will cover a distance of 15 miles. But Since he wants to spend more time on Running than on Cycling. We can Eliminate this.

40 - If he Cycles for 40 miles then the time taken will be 2 hours. Remaining 1 hour will be spent on Running, during which he will cover a distance of 10 miles. But Since he wants to spend more time on Running than on Cycling. We can Eliminate this.

50 - If he Cycles for 50 miles then the time taken will be 2 hour 30 minutes. Remaining 30 minutes will be spent on Running, during which he will cover a distance of 5 miles. But Since he wants to spend more time on Running than on Cycling. We can Eliminate this.

After we arrive at the conclusion 30 miles, we need not check again for 40 & 50 miles separately, and so they can be ignored.

He will cover 20 miles each while Running & Cycling, in 2 hours and 1 hour respectively.