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# Word Problems and Data Analysis: GED Test Prep (page 2)

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Updated on Mar 9, 2011

### Ratio

A ratio is a comparison of two quantities measured in the same units. It can be symbolized by the use of a colon—x : y or or x to y. Ratio problems can be solved using the concept of multiples.

Example

A bag containing some red and some green candies has a total of 60 candies in it. The ratio of the number of green to red candies is 7:8.How many of each color are there in the bag?

From the problem, it is known that 7 and 8 share a multiple and that the sum of their product is 60. Therefore, you can write and solve the following equation:

7x + 8x = 60

15x = 60

Therefore, there are 7x = (7)(4) = 28 green candies and 8x = (8)(4) = 32 red candies.

### Mean, Median, and Mode

To find the average, or mean, of a set of numbers, add all of the numbers together and divide by the quantity of numbers in the set.

Example

Find the average of 9, 4, 7, 6, and 4.

(Divide by 5 because there are 5 numbers in the set.)

To find the median of a set of numbers, arrange the numbers in ascending order and find the middle value.

• If the set contains an odd number of elements, then simply choose the middle value.
• Example

Find the median of the number set: 1, 3, 5, 7, 2.

First arrange the set in ascending order: 1, 2, 3, 5, 7,and then choose the middle value: 3. The answer is 3.

• If the set contains an even number of elements, simply average the two middle values.
• Example

Find the median of the number set: 1, 5, 3, 7, 2, 8.

First arrange the set in ascending order: 1, 2, 3, 5, 7, 8, and then choose the middle values, 3 and 5.

Find the average of the numbers 3 and 5:

= 4. The median is 4.

### Mode

The mode of a set of numbers is the number that occurs the greatest number of times.

Example

For the number set 1, 2, 5, 3, 4, 2, 3, 6, 3, 7, the number 3 is the mode because it occurs the most often.

### Percent

A percent is a measure of a part to a whole, with the whole being equal to 100.

• To change a decimal to a percentage, move the decimal point two units to the right and add a percentage symbol.
• Example

.45 = 45%

.07 = 7%

.9 = 90%

• To change a fraction to a percentage, first change the fraction to a decimal. To do this, divide the numerator by the denominator. Then change the decimal to a percentage.
• Example

• To change a percentage to a decimal, simply move the decimal point two places to the left and eliminate the percentage symbol.
• Example

64% = .64

87% = .87

7% = .07

• To change a percentage to a fraction, put the percent over 100 and reduce.
• Example

Keep in mind that any percentage that is 100 or greater will need to reflect a whole number or mixed number when converted.

Example

Here are some conversions you should be familiar with. The order is from most common to less common.