Question

Several times a week, Chuck goes to the gym to run andswim. When running, heburns 35 calories per minute. When swimming,he burns 30 calories per minute. He has found a way to burn 730 calories after exercising for a total of 23 minutes. If r is the number of minutes running and wis the number of minutes swimming, howlong does Chuck spend at each activity?

Answer 1

Chucks spent 8 minutes running and 15 minutes swimming

Explanation:

Here, we want to know the amount of time Chuck spends on individual activities.

since the total time spent for the burning is 23 minutes;

then ;

r + w = 23 ••••••••(i)

Now, the number of calories burnt to running for r minutes will be r * 35 = 35w calories

The number of calories burnt to swimming for w minutes will be w * 30 = 30w calories

The addition of both gives the total calories burnt;

Hence;

35r + 30w = 730 ••••••••(ii)

So we have two equations to solve simultaneously ;

From i; r = 23-w

Substitute this into ii

35(23-w) + 30w = 730

805 -35w + 30w = 730

35w -30w = 805-730

5w = 75

w = 75/5

w = 15 minutes

but r = 23 - w

r = 23 -15

r = 8 minutes