Two solutions of different concentrations of acid are mixed creating 40 mL of a solution that is 32% acid. One-quarter of the solution is made up of a 20% acid solution. The remaining three-quarters is made up of a solution of unknown concentration, c. Which equation can be used to determine c, the unknown concentration? 30c 10(0. 2) = 40(0. 32) StartFraction 3 Over 4 EndFraction left-parenthesis c right parenthesis plus left-parenthesis StartFraction 1 Over 4 EndFraction left-parenthesis 0. 2 right-parenthesis right-parenthesis equals 40 times 0. 32. (c) StartFraction 1 Over 4 EndFraction cup. (0. 2) = 40(0. 32) (c)( (0. 2)) = 40(0. 32) 30(c)(10(0. 2)) = 40(0. 32).