Question

A chemist has 200 mL of a 10% sucrose solution. She adds x mL of a 40% sucrose solution. The percent concentration, y, of the final mixture is given by the rational function:

The chemist needs the concentration of the final mixture to be 30%. How many milliliters of the 40% solution should she add to the 10% solution to get this concentration?

Answer 1

The first one is “ C “, the second one is “ D “ the last one is “ C “

Explanation:

:D

Answer 2

We need to add 400 ml of the 40% solution

Explanation:

We take the amount times the percent concentration and add what we mix to get the final concentration

We need the final mixture to be 30% and we have 200 +x milliliter added together so that will be the amount in the container

200 * 10 % + x* 40 % = (200+x) *30%

Change the percent to decimal form

200 * .10 + x* .40 = (200+x) *.30

Distribute the .30

20 + .4x = 60+.3x

Subtract .3x from each side

20 + .4x-.3x = 60+.3x-.3x

20 +.1x = 60

Subtract 20 from each side

20-20 +.1x = 60-20

.1x = 40

Divide by .1

.1x/.1 = 40/.1

x=400

We need to add 400 ml of the 40% solution