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The amount of weight that Sam loses is directly proportional to the number of hours he spends exercising. If Sam loses a pound of weight for each 3 hrs of exercise, how many hours must he spend exercising to lose 25 lbs?

A25 hrs
B50 hrs
C75 hrs
D80 hrs

Verified Answer :

SaramAnderson514

It should be C, 75 hours. To explain why this is, if there is one pound loss for each three hours of exercise, then multiplying you multiply 3 hours of exercise to 75 pounds to get the total number of how many hours is needed to lose 25 pounds.

Answer:

The answer is C. 75 hours.

Step-by-step explanation:

In order to determine the hours, we have to know about direct proportionality.

The direct proportionality happens when two variables increase at the same time and their rate is a constant. It means that if one variable is increased, so the other variable will be increased too.

I have attached an image that shows a graph of two variables with direct proportionality.

In this case, we can get the constant of both variables: losing weight and the spending time.

\(k=\frac{Weight}{Time}=\frac{1}{3} =0.33\)

Then we need to know how many hours Sam will spend to lose 25 lbs:

\(\frac{25}{T}=k=0.33\\ T=\frac{25}{0.33}\\ T=75.76\) hours.

Finally, Sam needs to spend 75 hours to lose 25 lbs.

View image rmanquelafquen

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