Question

A nurse is combining one solution with an 8% concentration of acid in water with another solution that has 15% concentration of acid in water.if the nurse use 120ml of 8% solution, what volume of 15% solution should be used to obtain a mixture with 12% concentration?

Answer 1

Answer:

160ml(important)

step by step explanation:

the ratio in which solution with 8% concentration and 15% concentration should be mixed to get a mixture with 12% concentration

= (15-12)% : (12-8)%

= 3:4

3x = 120 => x = 40

therefore, solution with 15% concentration to be used

= 4x = 4(40) = 160 ml

2nd method :

let sol. with 15% conc. be x and mixture with 12% conc. be y

x + 120 = y --(1)

8% of 120 + 15% of x = 12% of y

1/100(960 + 15x) = 12/100( x + 120)

960+ 15x = 12x + 1440

3x = 480 => x = 160 ml Answer