Six bells commence tolling together and toll at intervals of 2,4,6,8,10 and 12 seconds respectively. In 30 minutes, how

Question

Six bells commence tolling together and toll at intervals of 2,4,6,8,10 and 12 seconds respectively. In 30 minutes, how many times do they toll together?  
    
A. 4  
B. 10  
C. 15  
D. 16  
    
#yocketprep #examsQA

Vijaya Lakshmi K · Answer

Hello Varun,

Correct option is D
Since, LCM of 2,4,8,10 and 12 is 120. So, after each 120 seconds, they would toll together.
Hence, in 30 minutes, they would toll  
(30×60)/120
=15 times

But then the question says they commence tolling together. So, they basically also toll at the beginning. So, total tolls together =15+1=16

Hope this helps!

Six bells commence tolling together and toll at intervals of 2,4,6,8,10 and 12 seconds respectively. In 30 minutes, how

MASTERS

BACHELORS