Question 1117132
<br>
The other tutor worked the wrong problem....<br>
His initial equation says he is adding more pure sugar to an 80% sugar solution to get a 35% sugar solution; of course that isn't going to work.  An error in his algebra allowed him to come up with a wrong answer.<br>
If you are going to use his algebraic method for solving the problem, the original equation has to be
{{{.80(1000) = .35(1000+x)}}}<br>
You can finish the solution of the problem by that method if you want.<br>
When one of the ingredients being mixed is 0% one thing and 100% the other -- as in this case where you are adding 100% water and 0% sugar -- I find a different approach to the problem easier, as explained below.<br>
The original solution of 1000 cc of 80% sugar solution contains .80(1000) = 800 cc of sugar.
When the water is added, that same 800 cc of sugar is now 35% of the solution.
So the total volume of the solution is now 800/.35 = 2285.7 cc (approximately).
So the amount of water that needs to be added is 2285.7-1000 = 1285.7 cc.