KanissaSimranch
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Your classmate is starting a new fitness program. He is planning to ride his bicycle 60 minutes every day. He burns 7 calories per minute bicycling at 11 mph and 11.75 calories per minute bicycling at 15 mph. How long should he bicycle at each speed to burn 600 calories per hour?

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Respuesta :

nobillionaireNobley
Let the time he spent bicycling at 11 mph be x and the time spent bicycling at 15 mph be y, then
x + y = 60 . . . (1)
7x + 11.75y = 600 . . . (2)
(2) x 7 => 7x + 7y = 420 . . . (3)
(2) - (3) => 4.75y = 180
y = 180 / 4.75 = 38
x = 60 - 38 = 22

Therefore, he should bicycle 22 minutes at 11 mph and 38 minutes at 15 mph.

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