Sender: Joel Hammer
Subject: Logic Problem Help
Level: Middle (6-9)

Jose can run around the track in 40 seconds. Arthur runs with Jose but in the opposite direction. They meet every 15 second. How long will it take Arthur to make one trip around the track?


Hi Joel,

Every time they meet they have, together, completed one run around the track. The least common multiple of 40 and 15 is 120, so in 120 secs they meet at the starting point for the first time. Since 8 x 15 = 120 this is the eighth time that they meet. In that time Jose has completed 3 trips around the track (120 = 3 x 40). How many times has Arthur been around the track?



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