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. 15)
15.
A, B and C start at the same time in the same direction to run around a circular stadium. A completes a round in 252 seconds, B in 308 seconds and c in 198 seconds, all starting at the same point. After what time will they again at the starting point ?
Answer: Option
Explanation:
L.C.M. of 252, 308 and 198 = 2772.
So, A, B and C will again meet at the starting point in 2772 sec. i.e., 46 min. 12 sec.
Discussion:
66 comments Page 2 of 7.
Priya said:
2 decades ago
I didn't understand how you took 2772 into 46 minutes and 12 seconds.
(1)
Arvind Kumar said:
9 years ago
Whenever we need to find a number which will get divisible by certain numbers completely we take lcm. On the other case, if we need to find the number which will divide certain numbers completely we take HCf.
Here in case, we need to find the number which gets completely divide by 252, 308 & 198 that is why we are calculating LCM.
Here in case, we need to find the number which gets completely divide by 252, 308 & 198 that is why we are calculating LCM.
(1)
Shweta said:
10 years ago
@Liana.
To convert into minute = 2772/60 = 46 min and remainder is 12.
That's why 46 min 12 sec.
To convert into minute = 2772/60 = 46 min and remainder is 12.
That's why 46 min 12 sec.
(1)
Gargi said:
10 years ago
If LCM is 2772 then why we are dividing 2760 by 40?
(1)
Kiran soni said:
2 decades ago
How can I quickly find 2772 LCM ?
Please reply.
Please reply.
(1)
Luci said:
5 years ago
@Giridhar.
Can you explain in more detail? Please.
Can you explain in more detail? Please.
(1)
Sujay said:
2 decades ago
When to take lcm and when to take HCF is confusion ? please help.
(1)
Deepak said:
9 years ago
The Right answer is 46 minutes and 20 seconds, this is a correct solution which I am going to explain below:
Lcm of (252,308,198) is 2772 seconds.
Converting in minutes by dividing 60,
2772/60 = 46 minutes and 20 seconds.
Lcm of (252,308,198) is 2772 seconds.
Converting in minutes by dividing 60,
2772/60 = 46 minutes and 20 seconds.
Jothi said:
9 years ago
Why we take LCM for this problem? How to understand. Anyone please tell me.
Shyam hyd said:
9 years ago
@JOTHI
2/ 252 308 198=126 154 99,
2/ 126 154 99= 63 77 99,
7/ 63 77 99,
11/ 9 11 9,
9/ 9 1 9 = 1 1 1,
2 * 2 * 7 * 9 * 11 = 2772.
2772 sec. i.e., 46 min. 12 sec.
2/ 252 308 198=126 154 99,
2/ 126 154 99= 63 77 99,
7/ 63 77 99,
11/ 9 11 9,
9/ 9 1 9 = 1 1 1,
2 * 2 * 7 * 9 * 11 = 2772.
2772 sec. i.e., 46 min. 12 sec.
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