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. 18)

Problems on H.C.F and L.C.M

18.

The ratio of two numbers is 3 : 4 and their H.C.F. is 4. Their L.C.M. is:

Answer: Option

Explanation:

Let the numbers be 3x and 4x. Then, their H.C.F. = x. So, x = 4.

So, the numbers 12 and 16.

L.C.M. of 12 and 16 = 48.

Discussion:

35 comments Page 2 of 4.

Manish kumar said: 4 years ago

Let numbers be 3x and 4x.

LCM 12x.

Also 3x *4x=LCM*HCF.
3x*4x=12x.
X=4.
Numbers are 12, 16.

LCM =12x = 48 is the answer.

(4)

Nisha said: 1 decade ago

Please tell me why use h.c.f value instead of x

hcf * lcm= pro. of no
4*lcm=3x*4x
lcm=3x*4x/4

reply according to this

Suyash said: 1 decade ago

Hey jayshree

Given hcf = 4
=3x=3x4=12
4x=4x4=16
multiply 3 with 16 and 4 with 12 answer is 48

got it!

Rosy said: 1 decade ago

As nisha said,

a*b = lcm*hcf

3*4 = 4*lcm

We get value lcm = 3.

Why can't we do in this method?

Nikita said: 3 years ago

As x = 4.
And no's are given 3x and 4x.
Putting value of x in above equations
3(4) = 12,
4(4) = 16.

(4)

Homay said: 1 decade ago

HCF = 4 (given).
Say m = 4.

LCM = Product of two numbers/HCF.

= 3m*4m/m.
= 12*16/4.
= 48.

Kinjal said: 1 decade ago

I understand that assume numbers are 3x & 4x so hcf is x. But now how x is equals to 4?

Karan kashyap said: 1 decade ago

Easy and time saving trick is.

3:4= 3*4 = 12.

12*hcf=>>>> 12*4=48 answer.

Pranathi said: 8 years ago

4 * lcm=3x * 4x.
4 * lcm=3 * 4 * 4 * 4,
Lcm = 12 * 16 ÷ 4.
= 48 -> Is this correct?

Mayur said: 3 years ago

Let,
LCM = LCM of ratio units x(multiply) HCF.
LCM = 12 x 4(given),
LCM = 48.

(13)

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