Aptitude - Problems on H.C.F and L.C.M - Discussion

Discussion :: Problems on H.C.F and L.C.M - General Questions (Q.No.23)

23. 

Find the highest common factor of 36 and 84.

[A]. 4
[B]. 6
[C]. 12
[D]. 18

Answer: Option C

Explanation:

36 = 22 x 32

84 = 22 x 3 x 7

H.C.F. = 22 x 3 = 12.


Prasanna said: (Jun 8, 2010)  
I cant understand how this problem has solved ? actually what is the procedure ? tell me

Anshu said: (Dec 6, 2010)  
Can anyone explain this problem clearly.

Aparna said: (Dec 27, 2010)  
firstly find the prime factors of both the numbers
then choose the common prime numbers whose power is less
tats the hcf

Prashant Pandey said: (Feb 1, 2011)  
36/2=18
18/2=9
9/3=3
3/3=1

that is 2*2*3*3
similarly for 86 and then take comman prime between them
and then multiply as above

Sanjeeb,Angul said: (May 24, 2011)  
H.C.F OF 36 AND 84 is 12 so common factor is 12

Rajkumar said: (Jul 16, 2011)  
Similarly 84/2=42
42/2=21
21/3=7

Then we have to take the common on both sides i.e from 2*2*3*2 and 2*2*3*7. thus 2*2*3=12. Hence the answer is obtained.

Raviteja said: (Aug 22, 2011)  
H.C.F OF 36 AND 84 is

36)84(2
72
--
12)36(3
36
---
X
so H.C.F=12.

Parul said: (Jul 14, 2013)  
Simple method:

84-36 = 48.

48-36 = 12.

HCF = 12.

Teenuvarghese said: (Jul 31, 2014)  
H.C.F. = 22 x 3 = 12. I can't understand this line can any explain in this line?

Mahesh said: (May 8, 2015)  
Its so good and also so much help full to all.

Vinoth said: (May 13, 2017)  
36 = 2 * 2 * 3 * 3.
84 = 2 * 2 * 3 * 7.

The common values are 2 * 2 * 3 = 12.

Dhananjay Moundekar said: (Dec 12, 2017)  
36)84(2
-72
-------
12)36(3
-36
-----------
X

So, The Answer of the Que is 12.

Ashwin said: (Feb 20, 2018)  
How 12 come? HCF should b 6 na?

Vikash said: (Apr 14, 2018)  
36= (2)x(2)x(3)x3,
84= (2)x(2)x(3)x7,
Then take the pair that is common;
2x2x3=12.

Syed Sheraz Haider said: (Dec 12, 2018)  
36= 1*2*3*4*6*9*12*18.
84=1*2*3*4*6*12*14*21.

So, the HCF is 12.

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