LCM and HCF problem

Question : There are three numbers such that the product of the first two numbers is 91
                 and that of the last two numbers is 221. Find all three numbes and their sum



Answer :
Suppose numbers are A , B AND C.

Also given   A x B  = 91 and B x C = 221

Since the numbers are prime number, they contain only 1 as the common factor.

Also, above two products have B in common.

So, B = H.C.F. of ( 91 and 221 ) = 13;

A  = 91/13 = 7;  C  = 221/13 = 17.

Required sum = (7 + 13 + 21 ) = 41.



=================================================================

Question : The ratio of two numbers is 3 : 4. The L.C.M. of two numbers is 48.
                  Find sum of the number

Solution : Let the numbers be 3x and 4x.

Then, their L.C.M. = 12x.

So, 12x = 48 or x = 4

The numbers are 12 and 16.

Hence, required sum = (12 + 16) = 28.

lcm_hcf_questions

================================================================

lcm_hcf_gmat_question


Important points regarding LCM and HCF must remember for quantity exams like Bank PO

1) Least number which when divided by numbers gives same remainder in each case will be LCM of given number plus remainder 

      Example :  Find least number which when divided by 5 , 6 , 7 and 8 leaves remainder 2 ?
                        LCM ( 5 , 6 , 7 , 8 ) is 840
                         So  our answer is 840 + 2 = 842

2)  Largest number which divides to given numbers leaves same reminder , arrange the number in ascending order like a , b ,c then find out HCF of ( b-a , c-b . c-a )

 Example : Find the greatest number that will divide 42, 90 and 178 so as to leave the same remainder in each case. 

Answer is HCF of ( 178-90 , 90-42 , 178-42 ) = HCF of ( 88 , 48 , 136 ) =   8 and remainder 2



3) Largest number which divides X , Y and Z to leave remainder A ,B and C to find this
 calculate HCF of ( X - A  ,  Y - B , Z-c )






LCM and HCF defination  : http://maths4ur-kid.blogspot.in/2017/01/lcm-and-hcf-problem.html

Label : Maths for Kids , Maths Puzzle , Brain Tester ,  Maths Question , Time distance speed
             Maths Problems , Maths worksheet , LCM and HCF problem , LCM and HCF worksheet

Comments

  1. Shahabaz1 February 2017 at 10:47

    nice post buddy

    very good maths questions for kidskeep it up cheers

    ReplyDelete
  2. Liew-Ong Siew Bee2 February 2017 at 17:22

    thank you for your sharing

    ReplyDelete
    Replies
    1. Aishi6 February 2017 at 23:21

      welcome Liew hope you liked the post too

      Delete
  3. BnT4 March 2017 at 23:36

    very nice question for LCM and HCF..pl share some more questions

    ReplyDelete
  4. Aishi4 March 2017 at 23:41

    thanx and welcome to my blog maths for kids
    pl visit for more on lcm and hcf

    ReplyDelete
  5. noc9 March 2017 at 22:08

    Nice blog for maths , certainly it will help to your user. Nice question and explanation on LCM and HCF

    ReplyDelete
  6. BnT10 March 2017 at 12:50

    very nice and informative point shared in post on lcm and hcf

    ReplyDelete
  7. BnT17 May 2017 at 09:36

    Can you please put some more question on LCM and HCF...

    ReplyDelete
  8. Unknown15 June 2017 at 21:00

    Nice question lcm and hcf

    ReplyDelete
  9. Santosh15 June 2017 at 23:47

    Pl share some more questions on LCM and HCF for practice . certainly this will help for PO exams

    ReplyDelete
  10. mpandey4 February 2019 at 04:01

    Hello put some more question on lcm hcf

    ReplyDelete
  11. Unknown2 September 2020 at 05:25

    Nice,
    It'll help kids

    ReplyDelete
  12. Unknown2 September 2020 at 05:30

    one of the best post mate =)
    BlackyKing

    ReplyDelete

Post a Comment

Popular posts from this blog

Line of Symmetry

Image
Line of Symmetry This is a lesson on line symmetry for grades 3-4. It contains variety of exercises for the students. symmetry means that one shape becomes exactly like another. The line of symmetry is an imaginary line where you could fold an image and have both halves match exactly i.e.  if you placed a mirror along the symmetry line, you would see the other half of the figure reflected in the mirror. Exercise on line of Symmetry : Note : 1) Equilateral triangle has three line of symmetry while Isosceles triangle has only one line of symmetry.  2) Square has four line of symmetry while rectangle has two line of symmetry. Pl tell how many line of symmetry do  rhombus   and     parallelogram have
Read more

LCM and HCF

Image
Factor :   Factor for a given number are all the numbers which divides given number completely i.e. if you divide given number by factor then there will be no remainder. Question Write all the factors of 100 ? Prime Number : are the numbers which divided completely by only itself or one.               example 2 , 3 , 5 so on Question :   Write all the prime number till 100 ? ========================================================= HCF : Highest common factor of two or more number is the largest number that divide all the number completely    Factor of 10 are 1 ,  2  and 5    Factor of 15 are 1 , 3   and 5  so common factor of 10 and 15 are 1 and 5 in  which 5 is largest so HCF = 5 Note : HCF will be always less than the smallest number or equal to the smallest number.            HCF for prime numbers is 1. i.e there is no common factor other tha...
Read more