Question

how many liters (L) of 10% alcohol solution must be mixed with 50 L of 90% solution to get a 50% solution

Answer 1

0.1x+50(0.9)=0.5(x+50)
0.1x+45=0.5x+25
minus 0.1x both sides
45=0.4x+25
minus 25 both sides
20=0.4x
divide oth sides by 0.4
50=x
add 50 liters