What is the percent concentration of salt in the mixture?

Question

Ten liters of 25% salt solution and 15 liters of 35% salt solution are poured into a drum originally containing 30 liters of 10% solution. What is the percent concentration of salt in the mixture?

Answer 1

25% = 10

35% = 15

10% = 30

x% = 55

0.25(10) + 0.35(15) + 0.10(30) = x (55)

x = 19.55%