I would say to check your heart rate (sometimes treadmills have a handle grip thing for your heart rate)
Answer:
7 weeks
Explanation:
2500÷500 = 5 days
This means it takes 5 days to gain 1 lb
5 days × 10 lbs = 50 days
50÷7 = 7.14 ≅ 7 weeks
This results in Approximately 7 weeks for him to reach his desired weight.
I think it's B, it just makes the most logical sense to me.