Question: Ken can do 20 sit-ups without stopping. Nathan can do twice as many, and Bob can do half the number of Ken and Nathan's combined sit-ups. How many more sit-ups can Bob do compared to Ken? Think carefully first, then make a decision:
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Nathan can do 20 x 2 = 40 sit ups. Ken and Nathan's combined number is 20 + 40 = 60 sit - ups. Bob can do 60 / 2 = 30 sit - ups. Bob can do 30 - 20 = 10 more sit - ups than Ken. So the answer is 10.
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