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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)
Problems on H.C.F and L.C.M
7.
Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 2400. Their H.C.F. is:
40
80
120
200
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 3 of 5.
Harshitha Reddy said:   4 years ago
3x, 4x, 5x take LCM of these numbers is 60.
Formula:-numbers=LCM * hcf.
60x = 2400 * hcf,
X = 2400/60,
X = 40.
(3)
Karan said:   1 decade ago
Better way to find hcf for three numbers is either you could take the differences between them respectively.
Sundar said:   10 years ago
3x*4x*5x=2400x.

1x gets cancelled.

Then 60x^2=2400;

x^2=40.

Then x is 2 root 10; Answer is wrong.
(1)
Kishore said:   9 years ago
I did like this but fails.

3x * 4x * 5x = 2400 * (h.c.f = x)
Square of x = 40
Can anyone help me?
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?
Devraj chapagain said:   8 years ago
LCM = HCF*remaining factors.
or, 2400 = HCF *3 *4*5.
So, HCF = 2400÷60.
= 40.
(2)
Arunkumar s said:   9 years ago
Do the equation product of numbers = HCF * LCM only used in two numbers?
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
Paridhi said:   1 decade ago
Why is LCM 3x X 4x X 5x is the LCM equal to the product of the numbers?
Balachandra said:   8 years ago
2400/3 = 800
2400/4 = 600
2400/5 = 480
HCF of 800, 600.480 is 40.
(1)
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