Technical Mathematics, Sixth Edition

3.5. Applications Involving Mixtures

We turn now to mixture problems, a term which at first may seem very narrow. However, we will not only consider mixtures of liquids, like the oil/gasoline mixture in a snowmobile or chain saw but will also include the mixture of metals in an alloy like brass, the mixture of sand, stone, cement, and water in concrete, the mixture of solids and solvent in paint, and so forth.

3.5.1. Basic Relationships

The total amount of mixture is, obviously, equal to the sum of the amounts of the ingredients.

NOTE

These two ideas are so obvious that it may seem unnecessary to even write them down. However, it is because they are obvious that they are often overlooked. They state, in other words, that the whole is equal to the sum of its parts.

Example 32: From 100.0 lb of solder, half lead and half zinc, 20.0 lb is removed. Then 30.0 lb of lead is added. How much lead is contained in the final mixture? Solution: By Eq. 1001, final amount of lead = 50.0 + 30.0 − 10.0 = 70.0 lb

3.5.2. Percent Concentration

The percent concentration of each ingredient is given by the following equation:

NOTE

Example 33: The total weight of the solder in Example 32 is