A lab technician?

Question

A lab technician gets an order for 10 liters of a 20% saline solution. He has some 50% and 30% saline solutions in stock, so plans to mix the two with sufficient amount of water to produce the 20% solution. To conserve available resources, the water used was 4 liters greater thatn the sum of the other two ingredients. Find the amount of each ingredient used.
please put this in equations, and solve it.

Answer 1

C1V1=C2V2
where C1- original concentration
V1 - original volume
C2 - final concentration
V2 - final volume

For the 30 % saline solution:

C1 = 30 % ; V1 = is what is not known
C2 = 20 % ; V2 = 10 liters

so substituting; (30 %) ( V1) = (20 %) ( 10 liters)

V1 = (20 %)(10 Liters) divided by (30%) = 6.67 liters

For the 50 % , use the same formula:
V1= (20 %) ( 10 liters) divided by (50%) = 4 liters

If the water used is 4 liters greater than the sum of the two ingredients, then all you have to do is substitute 14 liters in place of the 10 liters and solve the problem making use of the same formula.