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.
Harsha Shende said:
8 years ago
Please give me an answer of this problem.
Least number which when divided by 5, 6, 7, 8 and leaves remainder 3 but when divided by 9 leaves no remainder?
Least number which when divided by 5, 6, 7, 8 and leaves remainder 3 but when divided by 9 leaves no remainder?
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).
Awanish said:
10 years ago
I am not agree with this explanation 1st beep at 0 sec so time start after 0 so within 30 min it beeps 15 times.
For 16 beep it takes 30 min 1 sec.
For 16 beep it takes 30 min 1 sec.
Chandra mouli R said:
8 years ago
In the question, it clearly states that all the bell starts tolling at first and then tolls at regular intervals,
So we have to add 1 with the 15.
So we have to add 1 with the 15.
Vishnu said:
8 years ago
Answer 15 is right.
The reason is we can't consider 0th sec bell together like in clock problem hour and min. Hand coincide 11 times in 12 hours.
The reason is we can't consider 0th sec bell together like in clock problem hour and min. Hand coincide 11 times in 12 hours.
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.
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?
Fozia sheikh said:
1 decade ago
Four bells toll after intervals of 8, 9, 12and 15minutes, respectively. If they toll together at 3pm. When will they toll together next?
Praful said:
7 years ago
15 should be the correct answer.
because
if, it is asked that how many times clock hands have coincided then the answer is 22 not 23.
because
if, it is asked that how many times clock hands have coincided then the answer is 22 not 23.
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.
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