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 4 of 17.
Suyash Raj said:
8 years ago
We know that 1st bell will commence on 0 min. Then in 30 min, 15 other bells will be tolling at every 2 min. Of interval. Therefore if we add all of these. Answer will be 15 + 1=16.
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.
Dk anbu said:
4 weeks ago
@Kyra.
Here, it is asked in 30 minutes how many times 6 ring balls roll together.
6 ring balls roll every 2 minutes
So, we divided for 30 minutes how many 2-interval exist.
Here, it is asked in 30 minutes how many times 6 ring balls roll together.
6 ring balls roll every 2 minutes
So, we divided for 30 minutes how many 2-interval exist.
Veenit said:
5 years ago
@Raksha.
1 is added because they commence together consider that at 0 sec.
Which mean first tolling happened at 0 sec,
2nd@120th sec,
3@240th sec and last happed @1800th sec.
1 is added because they commence together consider that at 0 sec.
Which mean first tolling happened at 0 sec,
2nd@120th sec,
3@240th sec and last happed @1800th sec.
(3)
Sathya said:
1 decade ago
Excellent sravan now I understand everything in the question n wt you said. Its really very helpful to me. , AND YOUR EXPLANATION IS VERY VERY CLEAR.
THAN YOU VERY MUCH sravan!
THAN YOU VERY MUCH sravan!
Deepak said:
1 decade ago
@neem
2=2
4=2*2
6=2*3
8=2*2*2
10=5*2
12=2*2*3
nw select d max count for 2 3 5
for 2. Its in 8. I.e. 2*2*2.
Then 5 n 3 are only once in any combination.
So lcm=2*2*2*3*5=120
2=2
4=2*2
6=2*3
8=2*2*2
10=5*2
12=2*2*3
nw select d max count for 2 3 5
for 2. Its in 8. I.e. 2*2*2.
Then 5 n 3 are only once in any combination.
So lcm=2*2*2*3*5=120
Bharath Simha reddy said:
9 years ago
@All.
Here, we should count 0 but 0 is the 60th second of the previous minute if we count this 0 it would be 30 minutes 1 second.
So please give me the correct solution.
Here, we should count 0 but 0 is the 60th second of the previous minute if we count this 0 it would be 30 minutes 1 second.
So please give me the correct solution.
Dhivakar said:
9 years ago
If all the bells starts to toll, it will get the toll together only at the 120th second. If a bell starts to tell, will it start from zero or directly from 120?
Vishnu said:
1 decade ago
So We need to count that first commence according to your answer.
But according to the question we need to find the time after first tolling together na ?
But according to the question we need to find the time after first tolling together na ?
Shahrukh said:
6 years ago
Why is 1 being added? How can at 0 sec they toll together? So why adding 1? When 1st toll is after 2 min then at 30th min they will toll 15th time. Thats it.
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