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 ?
26 minutes and 18 seconds
42 minutes and 36 seconds
45 minutes
46 minutes and 12 seconds
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 4 of 7.

Viswa said:   7 years ago
Thank you all for explaining the answer.

Shubham said:   7 years ago
Thanks for all the given explanation.

Nagul said:   7 years ago
@All.

Simple solution:

The L C M of given number = 2772
=> 2772 ÷ 60 we get 46 as quotient and 12 as a reminder.

Zikpe said:   6 years ago
Just take LCM of 252, 308 & 198.

LCM = 2772 seconds or 46 minutes 12 seconds.

Anitha said:   6 years ago
LCM is 2772.

So, 2772/60 = 46min 12sec.

Ramya said:   1 decade ago
Can anyone tell me how to take quick L. C. M for big numbers? please.

Kranthikumar said:   1 decade ago
When to take lcm & hcf. Its confusing.

Akshay said:   1 decade ago
I am quite weak in determing the LCM. How did you arrive to a conclusion of 2772 ? could you show me the workings?

Madhavi said:   1 decade ago
Actually my problem is- taking out LCM will give when they'll meet i.e. it'll give the time at which they'll meet again but it's not necessary that they meet at the starting point? I guess dean's logic is correct.

Anish said:   1 decade ago
Why do you take LCM?


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