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 6 of 17.
Pri said:
1 decade ago
Please explain me HCM. I can't get clear idea about it.
Upendra said:
1 decade ago
Why 1 added?
Saikiran said:
1 decade ago
Six bells commence tolling together means six bells started tolling together that's why 1 is added to 15, now 15+1=16.
Commence=Start or begin.
Commence=Start or begin.
Sumit chauhan said:
1 decade ago
But why are we add 1? Because when we toll together all the ball. They toll together. And that time also count in first 30 min.
Divi said:
1 decade ago
Very clear explanation. Thank you.
Shrinivasmutagar said:
1 decade ago
Why that 120 sec have been took?
Mahesh said:
10 years ago
How do you get that 120?
Gowthami said:
10 years ago
As they all together, why should we add 1, I couldn't understand. Why will first bell toll first, it starts together with the 5 bells know?
Akhil said:
10 years ago
4 bells ring at an interval of 12, 16, 20, 24 min if they start together at 9 am after how long will they ring together.
Sam said:
10 years ago
12 = 2*2*3.
16 = 2*2*2*2.
20 = 2*2*5.
24 = 3*2*2*2.
L.C.M = 2*2*2*2*3*5 = 240 min.
= 240 min/60 min = 4 hr.
So at 1 pm it will ring again (9+4).
16 = 2*2*2*2.
20 = 2*2*5.
24 = 3*2*2*2.
L.C.M = 2*2*2*2*3*5 = 240 min.
= 240 min/60 min = 4 hr.
So at 1 pm it will ring again (9+4).
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