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Mathematics I (Math 1132)

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Study Force Academy
Durham College, Mathematics
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  • 42 lessons
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  • 10 week duration

Mathematics I (Math 1132)

Percentage

A percent is a ratio whose second term is 100. Percent simply means parts per hundred. In this section, you will  be introduced to percent change, efficiency, error, and concentration problems. In addition, you will learn how to convert decimals and fractions to percent, and vice versa.

Let’s begin by learning how fractions and decimals are related to percent:

Converting a percentage to a decimal is as simple as dividing by 100. However, difficulty rises when converting from a decimal to fraction.

Finding the percent of a number

In these problems, they give you a percent (technically, a rate) and a base number, then expect you to find the output.

Part 2 is slightly more challenging because this time they give you the output (what you found in Part 1) and they expect you to find the base.

Percentage Change

A percentage change is when a quantity increases or decreases by a certain amount. In other words, when two numbers that are being compared involve a change, the original value is subtracted from the new value and the result divided by the original value. Keep in mind that percent change can be either or positive or negative, so make sure you indicate this in your answer.

Percent Efficiency

Percent efficiency is used to calculate inevitable power losses within a device. Because the output of any machine or device is always less than the input, the efficiency of the device acts as a measure of those losses.

Percent Error

The accuracy of measurement is also known as percent error. The percent error is the difference between the measured value and the known value, divided by the known value, expressed as a percent. Percent error can also be either or positive or negative, so make sure you indicate this in your answer. Let’s take a quick look at some problems:

Percent Concentration

Percent concentration applies to mixtures with two or more ingredients. The video below shows the formula you use to calculate this percent using two examples.

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