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:
(I'll type it out as an equation.)

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: ___ml

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:
   (I'll type it out as an equation.)

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: ___ml

anonymous · Answer

$$y=\frac{ 0.1(200)+0.4x }{ 200+x }\times100$$

paki · Answer

you wana to solve this...

anonymous · Answer

Is that a question or a statement?

paki · Answer

which one... ?

anonymous · Answer

"you wana to solve this... "
I was just curious if you were asking that or telling me that.

paki · Answer

you have given the equation.... so is that to be solved or what...?

anonymous · Answer

Ah I see now.
Using the equation given, I need to find the number of milliliters of the 40% solution that should be added to the 10% solution to get the concentration of 30%.

anonymous · Answer

If it helps, the title of assignment is "Modeling with Rational Functions".

anonymous · Answer

Never mind. I figured it out.:

30% = 0.3
Replace "y" in the equation with 0.3, and solve for x.