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 6 of 7.

Sams said:   7 years ago
Can you kindly explain in details because I don't understand? Please help me to get it.

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.

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

Virat said:   5 years ago
Just deduce it like this---->>

252 ---2*126 = 2^2*63 = 2^2*3*21 = 2^2*3^2*7.
308 ---2*154 =2^2*77 = 2^2*11*7.
198 ---2*99 = 2*3*11.
Now just take the prime factors with the highest power out.
So LCM = 2^2*3^2*7*11= 2772.
(4)

Isha said:   5 years ago
Thanks all for explaining the answer.
(1)

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


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