I have the answers; however, don't know how they came up with them.
Suppose a fountain has one shooter that shoots water every 3 seconds and another that goes off every 8 seconds. How long after the fountain is turned on will both shooters go off at the same time?
A third shooter shoots water every 16 seconds. Suppose all three shooters just went off together. How many seconds will pass before all three go off again at the same time?