Question

Five bells commence tolling together and tolls at intervals 3,6,9,12,nd 15 seconds respectively. in 45 mints how many times do they toll altogether

Answer 1

Five bells commence tolling together and tolls at intervals 3 , 6 , 9, 12 , 15 sec respectively.

toll altogether at LCM of {3, 6, 9, 12, 15}
prime factor of 3 = 1 × 3
prime factor of 6 = 1 × 2 × 3
prime factor of 9 = 1 × 3 × 3
prime factor of 12 = 1 × 2 × 2 × 3
prime factor of 15 = 1 × 3 × 5

toll altogether = 1 × 2 × 2 × 3 × 3 × 5
= 4 × 9 × 5 = 4 × 45 = 180 sec = 3min

number of times do they toll altogether
= 45 min/3min
= 15

hence, number of time do they toll altogether is 15

Answer 2

Acc to the ques,

Five bells commence tolling together and tolls at intervals 3,6,9,12,nd 15 seconds respectively.

So, LCM of the time intervals will be 3,6,9,12,nd 15 will be 180.

Now, the most important part is the conversion.

Question is asked in minutes, so we will convert 180 seconds to minutes.

1 min = 60 seconds.

180 seconds = 180/60 = 3 minutes.

Therefore no of times they toll altogether = 45 minutes / 3 minutes. = 15 times.