Thread: Solving for an unknown variable

Hi

How best can I approach this question?

A solution containing 45% water is mixed with another solution containing 10% bromine. If the chemist needs 30 liters of the mixture, how many liters of each solution are needed to make a 34.5% water/bromine solution?

Let x= water and y= the salt solution

"If the chemist needs 30 liters of the mixture"
x + y = 30 ...is that right?

Originally Posted by KayPee

A solution containing 45% water is mixed with another solution containing 10% bromine. If the chemist needs 30 liters of the mixture, how many liters of each solution are needed to make a 34.5% water/bromine solution?
Let x= water and y= the salt solution
"If the chemist needs 30 liters of the mixture"
x + y = 30 ...is that right?

Easier this way: let w = water ; then bromine = 30 - w

Code:

   w   @  .45
30-w   @  .10
====      ====
  30   @  .345

Can you turn that into an equation, then solve for w?