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 16 of 17.
Rahul said:
1 decade ago
Thanks Sravanreddypailla. Its truly good.
Nimmi said:
1 decade ago
But why have counted till 120. ?
Ali said:
1 decade ago
Excellent explanation sravanreddy
Gayatri said:
1 decade ago
Thank u deepak...
Krishna said:
1 decade ago
Thank you Sravan I got it.
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
Neem said:
1 decade ago
Can you please tell me how to calculate LCM of above series no. ? Please tell me.
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.
Kundharapu shravan reddy said:
1 decade ago
Excellent explanation sravanreddy.
Manju said:
1 decade ago
Awesome explaination sravan.
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