# 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

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.

 Saranya said: (Nov 11, 2020) Can you explain clearly?