You need 250 mL of a 90% alcohol solution. On hand, you have a 75% alcohol mixture. How much of the 75% alcohol mixture and pure alcohol will you need to obtain the desired solution?

9514 1404 393

Step-by-step explanation:

Let x represent the quantity (in mL) of pure alcohol needed for the mix. Then the amount of 75% needed is (250-x). The amount of alcohol in the mixture is ...

  1.00x +0.75(250 -x) = 0.90(250)

  0.25x +187.5 = 225 . . simplify

  0.25x = 37.5 . . . . . . . . subtract 187.5

  x = 150 . . . . . . . . . . . . . divide by 0.25

  (250 -x) = 100 . . . . mL of 75% solution

You need 100 mL of the 75% solution and 150 mL of pure alcohol to obtain the desired mixture.

first option

a function is a relation in which an input is paired with exactly one output.

so, let's find the right answer.

in our first option, our inputs are january, february, and march. the outputs are 30, 28, and 25. each input has it's own output. this is correct!

our second option we know is incorrect, because ms. valverade has two outputs, dogs and cats. this is not a function.

our third option is incorrect as well. the yellow square has two ouputs, the square and the triangle.

lastly, in our fourth option, we see the number 7 two times with a different output. therefore, this is not a function.

remember: each input must be paired with only one output!