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.

Vandan said:   4 years ago
It's simple, we have to only take out lcm which is 2772 and then convert it into time.
(2)

Ramin said:   4 years ago
Simply divide 2772 by 60.
You will get 46.
And remainder 12.
The remainder is seconds.
(3)

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

LCM = 2772 seconds or 46 minutes 12 seconds.

Syed Nadeem Asghar Rizvi said:   9 years ago
When I am doing 2772/60 (min) = 46.2 min is coming which means 46 mins. 2 secs.

Anyone said:   6 years ago
I have not understand what you said please show me the LCM how you have done.
(2)

Prahlad said:   8 years ago
2772 /60 =924/20 = 46minutes 4 seconds.
But 2772 /60 = 46minutes 12 seconds.

Jothi said:   8 years ago
Why we take LCM for this problem? How to understand. Anyone please tell me.

Priya said:   1 decade ago
I didn't understand how you took 2772 into 46 minutes and 12 seconds.
(1)

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

Sandy said:   8 years ago
2400 sec= 40min and 360 sec = 6 min. Remaining 12 sec (2400+360+12).


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