Question

the ratio of two numbers is 3:4 and thear L. C. M. is 180 the 1st number is?

Answer 1

Let the 2 numbers be 3x and 4x and HCF be x.

Using formula, a×b = LCM × HCF

3x × 4x = 180 × x
12x² = 180x
x = 180/12
x = 15

a = 3x = 3×15 = 45
b = 4x = 4×15 = 60
HCF = x = 15

Hope this helps :)

Answer 2

let the no/s be 3x and 4x with HCF = x
 as they are in the ratio 3:4 and x is a common factor on them.
then       a×b = HCF × LCM
        3x × 4x = x × 180
             12x² = 180x 
=12x² - 180x +0
=12x² - 180x + 0x + 0
=12x(x-15) 0(x-15)
=(12x+0)(x-15)
then x = 15,0
0 neglected as HCF cannot be 0
So the no/s would be 3x = 3(15)
                                        =45
                                   4x = 4(15)
                                        = 60

:) Hope this helps!!!
ALL THE BEST FOR UR EXAM!!! DO IT WELL!!!