Question

Two no are in ratio 3:4 if 10 is added to each no the ratio become 7:9 find the no.

Answer 1

let the no.s be 3x and 4x.five is added to each no . therefore,

the new no.s are 3x+5 and 4x+5 . it is given that the new ratio is 7:9. accordingly,

3x+5/4x+5=7/9

=> 3x+5=7/9(4x+5)

= 3x+5= 28x/9+35/9

=>3x-28x/9=35/9-5

-x/9=-10/9.

-x=-10/9*9

-x=-10

=>x=10

the original no.s were 3x and 4x respectively.we found x=10.

now the first no. 3x=3*10=30

the other no.=4*10=40

so the required no.s are 30 and 40.

VERIFICATION

we said the no.s are 30 and 40. now, lets verify by checking the ratio. 30/40= 3/4= the given ratio in the question. 5 is added to both. then the ratio, 35/45= 7/9 which is the ratio given in the question. hence, verified.