Complete question :
Ryan is choosing between two exercise routines. In Routine #1, he burns 22 calories walking. He then runs at a rate that burns 10.5 calories per minute. In Routine #2, he burns 39 calories walking. He then runs at a rate that burns 6.25 calories per minute. For what amounts of time spent running will Routine #1 burn at most as many calories as Routine #2?
Answer:
4 minutes
Explanation:
Given the following exercise routines :
Routine #1,
Walking : burns 22 calories walking. He then running : burns 10.5 calories per minute.
Routine #2,
Walking : burns 39 calories walking. He then running : burns 6.25 calories per minute.
Let number of tone spent running = t
Hence,
Routine 1 ; calories burned
22 + 10.5t
Routine 2 ; calories burned
39 + 6.25t
Equating the two equations :
22 + 10.5t = 39 + 6.25t
10.5t - 6.25t = 39 - 22
4.25t = 17
t = 17/4.25
t = 4