niyah0238
Answered

In the lab, Lena has two solutions that contain alcohol and is mixing them with each other. She uses 400 milliliters less of Solution A than Solution B.
Solution A is 20% alcohol and Solution B is 17% alcohol. How many milliliters of Solution B does she use, if the resulting mixture has 179 milliliters of
pure alcohol?



Answer :

sqdancefan

Answer:

  700 mL

Step-by-step explanation:

Lena wants to know how much of solution B she uses to obtain a mixture of solution A with 20% alcohol and solution B with 17% alcohol that contains 400 mL less of solution A, and has 179 mL of alcohol in it.

Setup

Let b represent the number of mL of solution B in the mixture. Then (b-400) will be the number of mL of solution A. The number of mL of alcohol in the mix is ...

  0.20(b -400) +0.17b = 179

Solution

Simplifying the equation gives ...

  0.37b -80 = 179

  0.37b = 259 . . . . . . add 80

  b = 700 . . . . . . . . divide by 0.37

Lena uses 700 mL of solution B (17%) for the resulting mixture to have 179 mL of pure alcohol.

__

Additional comment

That means there will be 300 mL of solution A, and the contributions from each solution are ...

  • 0.20×300 mL = 60 mL . . . . from solution A
  • 0.17×700 mL = 119 mL . . . . from solution B
  • total alcohol = 60+119 = 179 mL

Other Questions