Answer:
20 seconds
Step-by-step explanation:
Alarm 1 = every 10 seconds
Alarm 2 = every 5 seconds
Alarm 3 = every 4 seconds
If they all 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 it will take until they all sound at the same time again, find the lowest common multiple of the three alarm
Alarm 1 (every 10 seconds) = 20, 30, 40, 50, 60, 70, 80, 90,
Alarm 2 (every 5 seconds) = 10, 15, 20, 25, 30, 35, 40, 45, 50
Alarm 3 (every 4 seconds) = 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48
The lowest common multiple of Alarm 1 (every 10 seconds), Alarm 2 (every 5 seconds) and Alarm 3 (every 4 seconds) is 20 seconds
Therefore, they will all sound at the same time again in the next 20 seconds
