This past Saturday, Jack worked for 3 hours mowing the lawn and doing chores in the house. Mowing the lawn burns 352 calories per hour and doing chores burns 136 calories per hour. If he burned a total of 570 calories, how long did it take him to mow the lawn?

Question

Mathematics

Ibarra

27 April, 20:13

This past Saturday, Jack worked for 3 hours mowing the lawn and doing chores in the house. Mowing the lawn burns 352 calories per hour and doing chores burns 136 calories per hour. If he burned a total of 570 calories, how long did it take him to mow the lawn?

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Answers (1)

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Gracelyn Knight · Answer 1

Let x be the times in hours he mowed the lawn and y the time, in hours, he did chores Then

x + y = 3

also 352x + 136y = 570

From the first equation y = 3 - x, Plug this into second equation:-

352x + 136 (3 - x) = 570

216x = 570 - 136 (3) = 162

x = 162/216 = 0.75

so he spent 0.75 hours (or 45 minutes) to mow the lawn.