Lizzy: Colin ran his first mile in 6 minutes. He ran his next two miles in 5 minutes each and finished his 4th mile in 4 minutes. What was the average time it took him to run a mile?.
Me: Hmmm, let me think. I think this is the detailed solution:
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His first mile was in 6 minutes, then 5 minutes, another 5 minutes and his final mile was 4 minutes so it took him 6 + 5 + 5 + 4 = 20 minutes. It took 20 minutes to run 4 miles so his average time was 20 / 4 = 5 minutes per mile. Final answer: 5.
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