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.

Akshay said:   1 decade ago
Here every one should be at the same time according to question.

But after completion of 1 round not before it.

So each individual have to complete the round. That's why we have to consider their full time that's the reason to take LCM.

Dean said:   1 decade ago
It can't be determined unless the whole length of the track is given. Anyway, they will meet on the track again after 46 m 12 s but not necessarily at the starting point.

Deepak said:   8 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.

Renuka said:   10 years ago
L.C.M means just remember that the highest number should be taken and common factor for the all given numbers. I hope yow will understand.

Mahendra said:   10 years ago
How did you know that is to take LCM or HCF such types of questions?

Teja said:   10 years ago
After seeing this question I first thought, this question might be from TRAIN AND DISTANCE.

How can one know that we have to LCM for such kind of questions?

Vinay said:   10 years ago
Please tell me how to find L.C.M in quick time for far numbers?

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.

Kinjal said:   9 years ago
@Teja.

For train and distance question this question has inadequate data as there is no speed or distance given, hence we have to take it as L.C.M question.

Niha said:   9 years ago
Why we have to take LCM for this problem?


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