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 3 of 7.

Vijay said:   8 years ago
2772/60 = 46 min and remaining 12 sec.
or
2772/60=>693/15=>231/5 = 46 min 1/5.
1/5 =1 * 60/5 = 12 sec.
46 min 12 sec.

Rekha said:   1 decade ago
@Rehana.

Could you please explain when you took LCM of 63 77 99 with 7, how did it come out to be 9 11 9 (third step).

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.

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?

Hassan Raza said:   3 years ago
2772/60 = quotient = 46 ---> Minutes.
Remainder= 12----> second,
Thus, 46 minutes 12 second.
(10)

Shweta said:   9 years ago
@Liana.

To convert into minute = 2772/60 = 46 min and remainder is 12.

That's why 46 min 12 sec.
(1)

Atul Khanna. said:   1 decade ago
Anyone can you explain what is the total number of revolutions of each of them in above question?

Rehana said:   1 decade ago
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

Rahul said:   1 decade ago
How the lcm 2772 came ? when I calculated it is big enough than 2772. Please explain me.

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


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