SOLUTION: How much water should be mixed to a 500 mL of 30% solution of alcohol to have a resulting concentration of 20%?

Question 1062652: How much water should be mixed to a 500 mL of 30% solution of alcohol to have a resulting concentration of 20%?
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
you have 500 milliliters of 30% alcohol solution.

you want to add water to this solution so that it becomes a 20% solution.

the amount of alcohol in the 500 milliliters is .3 * 500 = 150 milliliters.

you want the same amount of alcohol divided by (500 + x) milliliters to be equal to 20%.

your equation would be 150 / (500 + x) = .2

x represents the number of milliliters of water to be added.

multiply both sides of this equation by (500 + x) and divide both sides of this equation by .2 to get:

150 / .2 = 500 + x

simplify to get 750 = 500 + x

solve for x to get x = 250.

you need to add 250 milliliters of water to get a solution that is 20% alcohol.

150 / 500 = .3 = 30%

150 / 750 = .2 = 20%
RELATED QUESTIONS
How much water should be mixed to a 500 mL of 30% solution of alcohol to have a resulting (answered by josgarithmetic)

How much water should be mixed to a 500 mL of 30% solution of alcohol to have a resulting (answered by josgarithmetic)

How much water should be mixed to a 500 mL of 30% solution of alcohol to have a resulting (answered by josgarithmetic,ikleyn)

How much water should be mixed to a 500 ml of 30% solution of alcohol to have a resulting (answered by Alan3354)

How much water should be added to 30 mL of 19% alcohol solution to reduce the... (answered by josgarithmetic,ikleyn)

how much water should be mixed with 6 gallons of 30% alcohol to get a 20% alcohol... (answered by jorel1380)

How much water should be added to 16 mL of 20% alcohol solution to reduce the... (answered by josmiceli,checkley77)

What will be the resulting volume and concentration (%) of a mixture, if 20 ml... (answered by josgarithmetic)