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 ?
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 1 of 7.
Hassan Raza said:
3 years ago
2772/60 = quotient = 46 ---> Minutes.
Remainder= 12----> second,
Thus, 46 minutes 12 second.
Remainder= 12----> second,
Thus, 46 minutes 12 second.
(10)
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)
Luci said:
4 years ago
@Giridhar.
Can you explain in more detail? Please.
Can you explain in more detail? Please.
(1)
Giridhar said:
4 years ago
Here 252,308,198.
Choose the biggest number.
308 check whether divisible by other 2 numbers i.e 252 and 198.
If not check for factors of 308 that would be lcm,
308/252 = 1.22.
308/198 = 1.55.
multiple of 308.
308*2.
Check further finally 308 * 9=2772.
2772/252 = 11.
2772/198 = 14.
Finally the answer is 2772 i.e 46min 12sec.
Choose the biggest number.
308 check whether divisible by other 2 numbers i.e 252 and 198.
If not check for factors of 308 that would be lcm,
308/252 = 1.22.
308/198 = 1.55.
multiple of 308.
308*2.
Check further finally 308 * 9=2772.
2772/252 = 11.
2772/198 = 14.
Finally the answer is 2772 i.e 46min 12sec.
(11)
Akhila said:
4 years ago
@Isa.
Your answer is very helpful. Thank you'.
Your answer is very helpful. Thank you'.
(5)
Madhan said:
4 years ago
2 [252,308,198]
2[126,154,99]
3[63,77,99]
3[21,77,33]
7[7,77,11]
11[1,11,11]
[1,1,1]
2*2*3*3*7*11=2772
Here, 60 sec = 1 minute.
Hence,
Simply divide 2772/60.
You will get 46.
And remainder 12.
Here, the remainder is seconds.
2[126,154,99]
3[63,77,99]
3[21,77,33]
7[7,77,11]
11[1,11,11]
[1,1,1]
2*2*3*3*7*11=2772
Here, 60 sec = 1 minute.
Hence,
Simply divide 2772/60.
You will get 46.
And remainder 12.
Here, the remainder is seconds.
(30)
Ramin said:
4 years ago
Simply divide 2772 by 60.
You will get 46.
And remainder 12.
The remainder is seconds.
You will get 46.
And remainder 12.
The remainder is seconds.
(3)
Isha said:
5 years ago
Thanks all for explaining the answer.
(1)
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.
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)
Anyone said:
6 years ago
I have not understand what you said please show me the LCM how you have done.
(2)
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