Question

the tail of two number is 5 : 7 if 40 is added in each number then the ratio become 25 : 31 find the number

Answer 1

Let the no. be x

so,

5x+40/7x+40=25/31

31(5x+40)=25(7x+40)

155x+1240=175x+1000

155x-175x=1000-1240

-20x=-240

20x=240

x=240/20

x=12

Answer 2

let the number be x

according to question

5x+40 / 7x+40 = 25/31

31x(5x+40) = 25x(7x+40)

155x².+1240x = 175x².+1000x

1240x-1000x = 175x²-155x²

240x = 20x²

-20x² +240x = 0

-x( 20x-240)=0

x= 240/20

X = 12