A certain neon sign flashes every 2 seconds, another sign flashes every 3 seconds and a third flashes every 5 seconds. If they all start flashing together how many seconds will it pass before all flash simultaneously again?

A certain neon sign flashes every 2 seconds, another sign flashes every 3 seconds and a third flashes every 5 seconds. If they all start flashing together how many seconds will it pass before all flash simultaneously again?

A 45

B 30

C 20

D 15

Solution

Correct Answer: Option B

২,৩,৫ এর ল.সা.গু. = ৩০