Question 1173603

A 15% lemon solution is added to a 5% lemon solution with the same amount in order to 
achieve a 10 liter of lemon solution with 10% concentration. How much 15% lemon 
solution was initially present?
<pre>You DON'T need to write a NOVEL, and go through complex calculations as the other person did. Unless of course, 
you're asked to form equations and solve for the initial amount of 15% solution.

Having said that, 15% down to 10% results in a 5% reduction, and 5% up to 10% results in a 5% increase.
Since the reduction and increase in percentages are the same, then EQUAL amounts were INITIALLY mixed, so {{{highlight_green(matrix(1,4, 5, L, of, "15%"))}}}.