Aptitude - Problems on H.C.F and L.C.M - Discussion
Discussion Forum : Problems on H.C.F and L.C.M - General Questions (Q.No. 3)
3.
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 ?
Answer: Option
Explanation:
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 | 30 | + 1 = 16 times. |
| 2 |
Discussion:
170 comments Page 5 of 17.
Pragati said:
7 years ago
Please anyone explain me again, I am not getting this.
Anubhav verma said:
7 years ago
@All.
1 is added because in the question there is given that the bells start tolling together, so 1 toll is there at the 0th second and afterwards they toll at every 120th second.
1 is added because in the question there is given that the bells start tolling together, so 1 toll is there at the 0th second and afterwards they toll at every 120th second.
Sunil said:
7 years ago
Just remember easily.
2,4,6,8,10,12.....take LCM, we get 120.
What they asking how many time toll together in 30 minutes
30minutes convert to seconds.
30*60=1800sec.
We have derived : 1800 ÷ 120=15.
At the time of zeroth sec tolls is 1 add total count 15+1=16.
2,4,6,8,10,12.....take LCM, we get 120.
What they asking how many time toll together in 30 minutes
30minutes convert to seconds.
30*60=1800sec.
We have derived : 1800 ÷ 120=15.
At the time of zeroth sec tolls is 1 add total count 15+1=16.
Name said:
7 years ago
How 120 come?
Please explain.
Please explain.
Bhavadip Gothadiya said:
7 years ago
Anyone explain to me, why to add additional 1?
Why (30/2) +1 instead of (30/2)?
Why (30/2) +1 instead of (30/2)?
Yamini said:
7 years ago
Why 1 is added here? Please explain.
Avinash said:
7 years ago
Please explain in an easy way as why lcm method to be used?
Prasanth v said:
7 years ago
30/2=15.
And 15+1=16 (added +1 reason is first 0 to 2 sec bell is tolled at a time).
And 15+1=16 (added +1 reason is first 0 to 2 sec bell is tolled at a time).
Rahul said:
7 years ago
Total 30 mins 1800 secs.
Coincide at 120 sec.
Divided the 1800/120=15+1=16.
Coincide at 120 sec.
Divided the 1800/120=15+1=16.
Pinky said:
7 years ago
Excellent explanation, Thanks @Saravan.
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