SOLUTION: A 150-lb person who runs at 6mph for 1hr burns about 720 calories. The same person, walking at 2 mph for 90 min, burns about 120 calories. Suppose a 150-lb person runs at 6 mph for

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Question 628750: A 150-lb person who runs at 6mph for 1hr burns about 720 calories. The same person, walking at 2 mph for 90 min, burns about 120 calories. Suppose a 150-lb person runs at 6 mph for 75 min. How far would the person have to walk at 2 mph in order to burn the same numberof calories as burned when running?
Answer by graphmatics(170) About Me  (Show Source):
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Let x be the number of calories generated per pound. let y be the calories generated per minute of speed. Then 150x+6*60y=720 150x+2*90y=120
150x+360y=720 150x+180y=120 we solve this system of equations
Solved by pluggable solver: Linear System solver (using determinant)
Solve:


Any system of equations:


has solution

or



(x=-3.2, y=3.33333333333333}

So x=3.2 and y=3.333333. For a 150 pound person running at 6 mph for 75 minutes the number of calories generated is 150*3.2+6*75*3.333333=1978.5 To find the distance covered at 2 mph we need to find the number of minutes required to generate 1978.5 calories so if z is the number of minutes 150*3.2+2*z*3.333333=1978.5.