Algebra
posted by Brittany .
Three ships leave New York for France on the same day. The round trip takes the first ship 12 days, the second ship 16 days and the third ship 20 days. How many days will elapse before all three ships again leave New York on the same day? Assume continuous trip activities for all three ships.

This is simply finding the Lowest Common Multiple of
12, 16, and 20
12 = 3x4
16 = 4x4
20 = 5x4
LCM = 4x3x4x5 = 240
240 days