Question

in what ratio should water be mixed with soda costing Rs 12 per litreso as to make a profit of 25%by selling the diluted liquid at Rs 13.75 per litre?

Answer 1

Original quality of soda = x liter
Cost of 1 liter soda = 12 rs
cost of x liter soda = 12x rs
let y liter of water is added with x liter of sode the ratio of soda and water be = x : y
Total quantity of mixture = ( x + y ) 
Cp of mixture = 12 x
Sp of ( x + y ) liter mixture = [13.75 (x + y )] =[1375 / 100 (x + y)]
Cp of mixture = sp + 100 / 100 + profit %
12x = 1375 / 100 ( x + y) * 100/100 + 25
12x =11 ( x+ y )
12x -11x = 11y
x = 11y
x/y = 11 : 1

Answer 2

Let he sold x litres of soda.

So cost price=12x

Profit=25%(given)

Hence Selling price=12x+((25/100)*12x)=15x

Let he mixed y litres of water.

Also,

Selling price=(x+y)*13.75

By condition,

(x+y)*13.75=15x

13.75y=1.25x

y/x=1.25/13.75=1/11

y:x=1:11