SOMEONE PLEASE HELP ME A science teacher has a supply of 20

SOMEONE PLEASE HELP ME!! A science teacher has a supply of 20% saline solution and a supply of 50% saline solution. How much of each solution should the teacher mix together to get 60 mL of 28% saline solution for his experiment?

Solution

Let x ml of 20% saline solution is mixed

Let y ml of 50% saline solution is mixed

x + y = 60 ml -----(1)

(0.2x +0.5y)/(x +y) =0.28 ----(2)

0.2x +0.5y = 0.28x +0.28y

-0.08x +0.22y =0 ----> 0.08x = 0.22y

solve both equations and get value of x and y :

x = 44ml of 20% solution

and y = 16ml of 50% solution