Question

Charlie mixes 15 liters of 17% acid solution with a 29% acid solution, which results in 23% acid solution.

Let x represent the number of liters of 29% solution used and let y represent the number of liters of mixture. Which system of equations can be used to find the number of liters of 29% acid solution in the mixture?

y = x + 15; 0.29y = 0.23x + 2.55

y = x + 15; 0.23y = 0.29x + 2.55

y = x + 15; 0.23y = 0.29x + 4.35

y = x + 15; 0.29y = 0.23x + 3.45

Answer 1

(15(.17)+.29x)/(15+x)=.23

2.55+.29x=3.45+.23x

.06x=.9

x=15

So 15L of the 29% solution was added to the 15L of 17% solution to make  

30L of 23% solution.