Question

A nurse needs to make 30 ml of 5% solution of glucose. She has available bottles containing 5 ml of 7% solution and bottles containing 10 ml of 1% solution. How many 5 ml bottles and 10 ml bottles will she need to make the solution?

Bottles of 5 ml of 7% solution needed:

Bottles of 10 ml of 1% solution needed:

Answer 1

amount of the 7% solution needed ---- x ml
amount of the 1% solution needed --- 30-x ml

.07x + .01(30-x) = .05(30)
7x + (30-x) = 5(30)
6x = 120
x = 20

She will need 20 ml of the 5%
and 10 ml of the 1% solution

since they come in 5 ml bottles
she will need 4 bottles of the 5% solution and
she wil need 2 bottles of the 1% solution

repeat for the other questions