$12 for 15 milliliters $8 for 10 milliliters yes or no

The correct answer is A. 167 milliliters of 7% solution and 333 milliliters of 4% solution and here is how:

If x is the number of milliliters of the 7% saline solution and y is the number of milliliters of the 4% saline solution then add up to 500 milliliters total, so x + y = 500.

and if we do

x + y = 500

x = 500 - y

0.07x + 0.04y = 25 (substitute 500 - y for x)

0.07(500 - y) + 0.04y = 25

35 - 0.07y + 0.04y = 25

-0.03y + 35 = 25

-0.03y = -10

y = 333.333...

y = about 333

x = 500 - y = 500 - 333 = 167

Then you know why the answer is A.

Step-by-step explanation:

step-by-step explanation: