What amount of a 45 acid solution must be mixed with a 30 so

What amount of a 45% acid solution must be mixed with a 30% solution to produce 300 mL of a 40% solution?

Let x ml of 45% acid is mexed with y ml of 30% solution is mixed

Total x+y = 300 ----(1)

0.45x + 0.3y = 0.4*300

0.45x + 0.3y = 120 ---(2)

4.5x +3y = 1200

Solve equation 1 and 2 get x and y

Multiply equation 1 by 9

we get 9x9y = -2700

9x+6y =2400

-3y =-300

y= 100 ml

x = 200ml

200 ml of a 45% acid solution must be mixed with a 30% solution to produce 300 mL of a 40% solution