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 2 of 17.
Manju said:
1 decade ago
Awesome explaination sravan.
Kundharapu shravan reddy said:
1 decade ago
Excellent explanation sravanreddy.
Nagaratna said:
1 decade ago
@Revathy
At first time all bells toll together at 120sec (i.e, 2 minutes).
But not only at 2 mins they toll together at multiples of 2mins they toll together. That means at 2min, 4min, 6min...........30min, 32,34,..........That is they continue the same.
But they have asked to find tolling only upto 30mins. So now if you divide 30min by 2 you will get 15.
At first time all bells toll together at 120sec (i.e, 2 minutes).
But not only at 2 mins they toll together at multiples of 2mins they toll together. That means at 2min, 4min, 6min...........30min, 32,34,..........That is they continue the same.
But they have asked to find tolling only upto 30mins. So now if you divide 30min by 2 you will get 15.
Neem said:
1 decade ago
Can you please tell me how to calculate LCM of above series no. ? Please tell me.
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
Krishna said:
1 decade ago
Thank you Sravan I got it.
Gayatri said:
1 decade ago
Thank u deepak...
Ali said:
1 decade ago
Excellent explanation sravanreddy
Nimmi said:
1 decade ago
But why have counted till 120. ?
Rahul said:
1 decade ago
Thanks Sravanreddypailla. Its truly good.
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