algebra
posted by Anonymous .
How many liters of a 20% solution of acid should be added to 10 liters of a 30% solution of acid to obtain a 25% solution?
Equation:
Answer:

looks very similar to the question just posted by Lily.
let the amount of 30% solution we want to add be x l
now let's reason it through....
the volume of acid we have before adding is .3(10) l or 3 l
we are adding x l of a 20% solution so we are adding .2x l
but the final solution containing 10+x l is to contain 25% acid or .25(10+x) l of acid
so isn't our equation...
3 + .2x = .25(10+x) ?
solve for x and tell me what you got. 
How many liters of a 8% solution of acid should be added to 20 liters of a 60% solution of acid to obtain a 40% solution?