A chemist has milliliters of a solution of alcohol on hand, and she wants to mix it with enough alcohol solution to turn it into a alcohol solution. If is the amount of alcohol she needs, which equation can she use to solve for ?

Read the following problem:

A scientist needs one liter of 20% hydrochloric acid solution; however, he only has two one-liter bottles of solution on hand, one of which is 15% acid and one of which is 35% acid. How much of each solution must he mix together to get the solution he wants?

Let be the number of milliliters of 15% solution he will use and be the number of milliliters of 35% solution he will use. Which of the following systems of equations will yield the correct values of both?

24 coins, all nickels and dimes, are together worth $1.75.

How many of the coins are nickels?

A scientist has one liter of a 40% sulfuric acid solution; he needs to dilute it to 25%. How much water will he need to dilute it to the appropriate strength?

Round your answer to the nearest tenth of a liter, if applicable.

A nut mixture consists of peanuts, pistachios, and macadamia nuts in the ratio , respectively, by weight. What amount of pistachios will be in 40 pounds of the mixture?

A scientist needs a 10% saline solution for an experiment. In his closet he finds a 20 ounce bottle of 25% saline solution. How many ounces of pure water should he add to the mixture to produce the correct saline solution?

A chemist wants to make one liter of hydrochloric acid solution. He only has two concentrations on hand - and . If is the amount in milliliters of the solution he is to use, then which equation can be used to solve for ?

Before being slightly dried, an apple is made of of water. After the apple is slightly dried, the water accounts only for of the weight of the fruit. Originally, the apple weighed . What is its weight after being dried? Consider the difference in weight to be solely caused by the evaporating water.

Mike, the barista at Moose Jaw Coffee, has to mix together two kinds of coffee beans - Mocha Madness, which costs $12 a pound, and Sumatra Sweetness, which costs $20 a pound - to produce forty pounds of a coffee that costs $14 a pound. The beans in the mixture sell for the same price as they would separately.

How many pounds of Mocha Madness coffee will Mike put into the mixture?

How much of a 20% acid solution would a chemist have to mix with one liter of a 40% acid solution to yield a 36% acid solution?