Question

Simon can see two lights, light A and light B.

Light A flashes every 15 seconds.
Light B flashes every 18 seconds.
At 10 pm, both lights flash at the same time.
How many more times will both lights flash at the same time in the next 4
minutes?​

Answer 1

2 Times

Explanation:

Simon can see two lights A and B

• Light A flashes every 15 seconds.
• Light B flashes every 18 seconds.

First, we determine the next time both lights will flash together.

This is done by finding the Least Common Multiple of 15 and 18.

15=3X5

18=
`2X3^2`

LCM of 15 and 18=
`2X3^2X5=90`

This means that lights A and B will first flash together after 90 seconds.

Now, 240/90=
`2.\overline{6}` seconds

Therefore, the number of times more both light will flash together in the next 4 Minutes= 2 Times