One car alarm is set to go off every 10 seconds. Another car alarm is set to go off every 5 seconds, and a third car alarm is set to go off every 4 seconds. If they all start to go off at the same time due to a loud clap of thunder, how long will it take until they all sound at the same time again?

20 seconds

Step-by-step explanation:

Car A = every 10 seconds

Car B = every 5 seconds

Car C = every 4 seconds

If they all start to go off at the same time due to a loud clap of thunder, how long will it take until they all sound at the same time again?

To determine how long will it take until they all sound at the same time again, find the lowest common multiples of cars alarm time

Car A (every 10 seconds) = 20, 30, 40, 50, 60, 70, 80, 90

Car B (every 5 seconds) = 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60

Car C (every 4 seconds) = 8, 12, 16, 20, 24, 28, 32, 36, 40

The lowest common multiples of the cars alarm time is 20 seconds.

Therefore, it will take 20 seconds for they all sound at the same time again