Question

Two bottles contain acid and water in the ratio 2 : 3 and 1 : 2 respectively. These are mixed in the ratio 1 : 3. What is the ratio of acid and water in the new mixture

Answer 1

Let  V Liters of mixture from bottle 1  be mixed with  3 V liters of the mixture from bottle 2.

So in the final mixture we have :
   V*2/(2+3) liters of acid  and  V*3/(2+3) liters of water     : from bottle 1
  (3V)*1/(1+2) liters of acid  and  (3V)*2/(1+2) liters of water   : from bottle 2

ie.,   2V/5 + V liters of acid     and   3V/5  + 3V  liters of water
        7 V/5  litres of acid    and     18 V /5  litres of water

Ratio of acid : water   =  7 : 18