Question

How much pure alcohol should be added 600ml of 20% of strength to get its strength 40%

Answer 1

Answer:

Volume of alcohol in 400 ml solution =0.15*400 ml

Volume of alcohol in 400 ml solution =60 ml

Volume of others liquid = 340 ml

Let x ml of alcohol is added to make it 32% strong

Then, volume of alcohol = 60+x ml

Volume of other liquid = 340 ml

Volume of solution = 400 + x ml

0.32*(400+x)=60+x

Or, 128+0.32x=60+ x

Or, 0.68 x = 68

Or, 68 x =6800

x=100

=> 100 ml of alcohol must be added.