In what ratio should water be mixed with soda costing Rs. 12 per litre so as to make a profit of 25% be selling the diluted liquid at Rs. 13.75 per litre?
S.P = 13.75
P = 25 %
S.P = C.P x 125/100
13.75 = C.P x 125/100
C.P = 11 Rs.

W: S = 1:11