Joe, Sarah, and Bob are all riding their bikes around the neighborhood. Joe can complete a lap around the neighborhood in 15 seconds. Sarah can complete a lap around the neighborhood in 20 seconds. Bob can complete a lap around the neighborhood in 30 seconds. At what time will all 3 complete a lap around the neighborhood at the same time? Show your work.

The 3 will complete a lap around the neighborhood in 60 seconds ( 1 minute)

Step-by-step explanation:

The time each of the three can take is 15 , 20, 30 seconds

Now, we want to calculate the time at which all 3 will complete a lap around the neighborhood at the same time

To calculate this, we simply look for the lowest common multiple of the three numbers

The lowest common multiple of 15, 20 and 30 seconds is 60 seconds ( 1 minute)