three feed stream $($all containing water$)$ are mixed and heated in a continuous process. Some of the water is lost by evaporation. The feed stream flow rates and compositions are as follows:

"Feed stream $1$: $50$ lbm$/$h of a salt solution consisting of $40$ mass$\%$ salt and the remaining is water."

"feed stream $2$: $100$ lbm$/$h of a sugar solution consisting of $20$ mass$\%$ sugar, and the remainder is water."

"feed stream $3$: $40$lbm$/$h of a waste solution consisting of $10$ mass$\%$ salt, $5$ mass$\%$ sugar, and the remainder is water."

If the final mixture contain $15$ mass$\%$ salt, what percentage of the total water fed is lost through evaporation? your solution must include a degree of freedom analysis that demonstrates the problem is slovable.

answer: $20\mathrm{.}8\%$