A nurse mixes 40 cc of a 60% saline solution with a 30% saline solution to produce a 38% saline solution. How much of the 30% solution should he use?

Answer 1

X is the amount of the 30% saline solution.

So there is 40+x cc of the finished product, which contains

38% saline.

The saline content is:

60% of 40 + 30% of X = 38% ( x+ 40)

24 + 0.3X = 0.38(x+40)

24 + 0.3X = 0.38X + 15.2

8.8 + 0.3X = 0.38X

8.8 = 0.08X

880 = 8X

X = 110

check:

0.6 * 40 + 0.3 * 110 = 24 + 33 = 57 = 150 * 0.38 = (110 + 40) * 0.38

YES, it checks

110 cc of 30% solution is needed to pull this off