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. 7)
7.
Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 2400. Their H.C.F. is:
Answer: Option
Explanation:
Let the numbers be 3x, 4x and 5x.
Then, their L.C.M. = 60x.
So, 60x = 2400 or x = 40.
The numbers are (3 x 40), (4 x 40) and (5 x 40).
Hence, required H.C.F. = 40.
Discussion:
41 comments Page 4 of 5.
P.vinothini said:
1 decade ago
Please if you don't mine reply what is mean by co-prime?
Sanjay said:
1 decade ago
Can this approach be applied for any higher co-prime numbers ?
Karan said:
1 decade ago
Better way to find hcf for three numbers is either you could take the differences between them respectively.
Brajesh said:
1 decade ago
If h.c.f is given then just do 3*4*5=60 and then 6o*40(h.c.f given)=2400
Rahul said:
1 decade ago
If given HCF what can I do. ?
Achu said:
1 decade ago
Easy method
3*4*5 = 60
2400/60 = 40
3*4*5 = 60
2400/60 = 40
Anurag said:
1 decade ago
@shrimant....
The formula works only for two number..for eg take num
2,4,8....hcf is 2
lcm is 16.
product of hcf and lcm=32
product of num=64.
The formula works only for two number..for eg take num
2,4,8....hcf is 2
lcm is 16.
product of hcf and lcm=32
product of num=64.
Shrimant said:
1 decade ago
In the explanation answer,the formula has been used is
Factor of number 3x={3,x}
Factor of number 4x={4,x}
Factor of number 5x={5,x}
Therefore,LCM is a product of {3,4,5,x} [x has taken once as it is common] i.e.LCM=60x
60x=2400
x=40
But,
If we take another formula that
Product of all numbers = Product of LCM and HCF
3x*4x*5x=2400*x
60x3[x to the power 3 or x cube]=2400x
x3[x to the power 3 or x cube] 2400
------------------------------ = ------
x 60
x2[x to the power 2 or x square]=40
therefore, x= square root of 40
then?
Can anybody solve my query???
Factor of number 3x={3,x}
Factor of number 4x={4,x}
Factor of number 5x={5,x}
Therefore,LCM is a product of {3,4,5,x} [x has taken once as it is common] i.e.LCM=60x
60x=2400
x=40
But,
If we take another formula that
Product of all numbers = Product of LCM and HCF
3x*4x*5x=2400*x
60x3[x to the power 3 or x cube]=2400x
x3[x to the power 3 or x cube] 2400
------------------------------ = ------
x 60
x2[x to the power 2 or x square]=40
therefore, x= square root of 40
then?
Can anybody solve my query???
MKR said:
1 decade ago
600,800,1000 commom divisor is :200
600)800(1
600
---------
200)600(3
600
---------------
0
---------
200)1000(5
1000
-------
0
----------
so 200 is the H C F.............
600)800(1
600
---------
200)600(3
600
---------------
0
---------
200)1000(5
1000
-------
0
----------
so 200 is the H C F.............
Vicky said:
1 decade ago
Can anyone say if instead H.C.F is given in place of L.C.M.
And asked to find L.C.M?
And asked to find L.C.M?
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