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7th of September 2015
Mathematics
Q:

five bells begin to toll together and toll respectively at intervals of 6,7,8,9and12 seconds.How many times they will toll together in one hour excluding the one at the start

Mkvinvestments6 Vijayvargiya - CBSE - Class X

Monday, September 07, 2015 at 18:32:PM

A:

hi

6 = 2x3 
7 = 7 
8 = 2x2x2 
9 = 3x3 
12 = 2x2x3 

Lowest common multiple is: 504. Five bells toll coincide at every 504 seconds 

Five bells will toll toghether at 504, 1008, 1512, 2016, 2520, 3024 and 3528 seconds.

The answer would be, then five bells will toll toghether  7 times in one hour, excluding the one at the start.

Monday, September 07, 2015 at 18:47:PM