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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

Answer: Option D

Solution(By Examveda Team)

L.C.M. of 2, 4, 6, 8, 10, 12 is 120.
So, the bells will toll together after every 120 seconds(2 minutes).
In 30 minutes, they will toll together
$$\frac{{30}}{2}$$ + 1 = 16 times

This Question Belongs to Arithmetic Ability >> Problems On H.C.F And L.C.M

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Comments ( 8 )

  1. Abhay Pratap
    Abhay Pratap :
    1 year ago

    why did we add 1

  2. Sajid Hasan
    Sajid Hasan :
    2 years ago

    why adding plus 1

  3. Ravi Kumar
    Ravi Kumar :
    4 years ago

    in six bell=2,4,6,8,10,12.,if we count the digit of all given no.=6,
    so answer should be the vice versa of question ,means
    so in 30 min tolling of bell like,0,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30.
    total no of digit =16,
    so ans =16.
    note=counting should be starting from the 0.

  4. Ashok Gupta
    Ashok Gupta :
    4 years ago

    But,if it start at 1 i.e last time they toll together at 11,then it should be 1,3,5,7,9,11,13,15,17,19,21,23,25,27 and 30

  5. Meet Kankariya
    Meet Kankariya :
    6 years ago

    0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

  6. Meet Kankariya
    Meet Kankariya :
    6 years ago

    They all missed their 24

  7. Abhijit Pradhan
    Abhijit Pradhan :
    6 years ago

    2,4,6,8,10,12 lcm is 120
    1min=60 sec
    120 sec= 2 min
    .: ever 2 mins one bell
    30 mins
    0,2,4,6,8,10,12,14,16,18,20,22,26,28,30
    Count all series =16 time
    Ans-C

  8. Vaibhav Jain
    Vaibhav Jain :
    7 years ago

    I don't understand how 16 times they will toll together. According to me the answer should be 15 times.

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