Question

Three bells toll at intervals of 9,12,15 minutes respectively.If they start tolling together after what time will they next toll together?

Answer 1

Hey there!
Time when they will toll together =LCM of 9,12,15=180
Hence the bells will start tolling together after 180 minutes.
Hope that helps you ✌️

Answer 2

This problem based on the concept

of LCM.

Here we have to find LCM of intervals

9 , 12 , 15 minutes which indicates

after how long they all again toll

together.

Write 9 , 12 and 15 product of prime

factors,

9 = 3 × 3

12 = 2 × 2 × 3

15 = 3 × 5

LCM( 9 , 12 , 15 ) = 3 × 3 × 2 × 2 × 5

= 180

Three bell toll together after 180

minutes .