How much water should be added to 80 grams of common salt so as to obtain 20% salt solution​

Concentration of solution is 20%

Mass of solute( common salt) is 80g

take the amount of water as x

mass of the solvent = (80+x)

We know, concentration of solution = (mass of solute/mass of solution)×100

20=(80/80+x)×100

80+x=80×5 ( we devide the both side by 20)

x= 400-80

x=320 g

The answer options is d