Jill Sharp, a fitness trainer, has an exercise regimen that includes running, swimming, and walking. She has no more than 12 hours per week to devote to exercise, including at most 4 hours running....

Jill Sharp, a fitness trainer, has an exercise regimen that includes running, swimming, and walking. She has no
more than 12 hours per week to devote to exercise, including at most 4 hours running. She wants to walk at
least three times as many hours as she swims. Jill will burn on average 528 calories per hour running, 492
calories per hour swimming, and 348 calories per hour walking. How many hours per week should Jill spend
on each exercise to maximize the number of calories she burns? What is the maximum number of calories she
will burn? (Hint: Write the constraint involving walking and swimming in the
form ? 0.)
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