Question 261069
Let 1% codeine syrup added to the mixture be x ml
Let 3% codeine syrup added to the mixture be y ml

x+y = 1000 ml---------- 1

 (1/100)*x + (3/100)*y = 1000* (2.5/100)
0.01x+0.03y = 25 -----2

Multiply eq. 1 by 0.01    then subtract from eq 2

0.01x+0.01y=10

0.02y = 15
y= 15/0.02  = 750 ml  = 3% solution.
                        250ml  = 1% solution.


M Ananth------- mananth@hotmail.com