80g of a 35% salt solution

The total weight is 80g, this is equal to the weight of the salt in the mixture plus the weight of the water in the mixture.

Ws = Weight of the salt

Ww = Weight of the water.

Then:

Ww + Ws = 80g

and the solution is 35% salt, so we have:

Ws/80g = 0.35

We must solve the system of equations, we can write the second equation as:

Ws = 80g*0.35 = 28g

Then we have 28 grams of salt, and the other 62g must be of water.