Question

The lcm and hcf of two numbers are 84 and 21, respectively. if the ratio of two numbers be 1 : 4, then the larger of the two numbers is

Answer 1

LCM×HCF=products of the two no.
84×21=4xsquare
xsquare=84×21/4
xsquare=21×21
X=√21×21
X=21
I hope it will help you bro.

Answer 2

Let the numbers are x and 4x
LCM ×hcf = product of two numbers
84×21=x ×4x
X^2 = 21×21
X= 21
Larger no. = 4× 21
=84