Question

A light display has three colored lights, each of which flashes on for an instant at regular intervals.the yellow one flashes 4 times per minute, the blue one flashes 6 times per minute, and the red one flashes on 30 times per minute. you see all the lights flash on simultaneously. how much longer must you wait before the three lights flash on simultaneously again?You must wait _____ before the three lights flash on simultaneously again.

Answer 1

Answer:

You must wait 50 seconds before the three lights flash on simultaneously again. ​

Explanations:

Note:

1 minute = 60 seconds

The yellow light flashes 4 times per minute

Time taken by the yellow light to make a flash = 60 /4 = 25 seconds

The blue light flashes 6 times per minute

Time taken by the blue light to make a flash = 60/6 = 10 seconds

The red light flashes 30 times per minute

Time taken by the red light to make a flash = 30/6 = 5 seconds

The time taken for the three lights to flash simultaneously is the Lowest common Multiple (LCM) of the time taken by each of them to make a flash

The LCM of 25, 10, 5 = 50

Therefore, the three lights will flash simultaneously after every 50 seconds