Question

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

Answer 1

Hint: In order to solve this problem you need to find the lowest common factor of the times given. it will give you the right answer.

Complete Step-by-Step solution:
It is given that three bells tolls at the intervals of 9, 12, 15 minutes respectively.
We need to find out if they start tolling together after what time they next toll together.
LCM of 9, 12, 15 can be found as:
On doing factorization of 9, 12 and 15 we get,
9 = 3 x 3
12 = 2 x 2 x 3
15 = 5 x 3
LCM can be written as = 3 x 3 x 2 x 2 x 5 =180
So, the answer is 180.
If they start tolling together then it will rung after 180 minutes.

Note: In order to solve this problem you just need to find the LCM of the time given to get the time after which the bells toll together. We have taken LCM by factoring each term and then written common factor once then multiplied with all other non-common factors to get LCM. Doing this will solve your problem and will provide you the right answer.