GED Math - Proportions and Percentages

At a party, there are 7 women with blonde hair, 9 women with brown hair, and 5 women with red hair. What is the proportion of women with blonde hair?

$\small \frac{1}{3}$

$\small \frac{1}{2}$

$\small \frac{7}{9}$

$\small \frac{7}{5}$

Explanation

A proprotion is the number of a specific event (blonde women) divided by the total number of events (total number of women).

$\small \frac{7}{7+9+5}=\frac{7}{21}=\frac{1}{3}$

Solve:

$14%\ of\ 52=$

Explanation

$\small 14%\ of \ 52=0.14\times 52=7.28$

At a zoo, the ratio of birds to mammals to reptiles is 2 to 5 to 6. If there are a total of 195 birds, mammals, and reptiles, how many reptiles does the zoo have?

The number of reptiles cannot be determined from the information given.

Explanation

To maintain the correct ratio of birds to mammals to reptiles, let be the number of birds, be the number of mammals, and be the number of reptiles.

We can then write the following equation:

Solve for .

Since the question asks for the number of reptiles, we will need to find the value of .

The zoo has reptiles.

Solve: $\frac{3}{2x} = \frac{4}{7}$

$\frac{21}{8}$

$\frac{8}{21}$

$\frac{1}{13}$

$\textup{No solution.}$

Explanation

Cross multiply the terms.

Divide by eight on both sides.

$\frac{21 }{8}=\frac{ 8x}{8}$

The answer is: $\frac{21}{8}$

What is of of of ? Round to the nearest hundredth.

Explanation

For percentage problems, the following is the easiest way to get to the correct answer. Always convert the following:

"is":

"of":

For your problem, it is relatively easy. First convert your percentages into the following decimal values:

Therefore, your answer is merely:

Round this to

What is 25% of 240?

Explanation

To find a percentage of a whole number, we will multiply the two together. So, we get

$25% \cdot 240$

$\frac{25}{100} \cdot 240$

$\frac{25}{100} \cdot \frac{240}{1}$

Now, the zero in 100 and the zero in 240 can cancel. We get

$\frac{25}{10} \cdot \frac{24}{1}$

$\frac{25 \cdot 24}{10 \cdot 1}$

$\frac{600}{10}$

$\frac{60}{1}$

Therefore, 25% of 240 is 60.

A salesman for a car dealership earns 15% commission on all sales. What will be his commission for a week if he sells three cars that week - a $35,000 SUV on Tuesday, a $24,000 car on Thursday, and a $40,000 van on Friday?

Explanation

The total sale price of the cars he sells will be

15% of $99,000 is

$$ 99,000 \times 0.15 = $14,850$ ,

which is the salesman's commission.

Solve the proportion: $\frac{2x}{5} = \frac{7}{3}$

$\frac{ 35}{6}$

$\frac{7}{3}$

$\frac{6}{35}$

Explanation

Cross multiply the terms.

Divide by six on both sides.

$\frac{6x }{6}=\frac{ 35}{6}$

The answer is: $\frac{ 35}{6}$

To get on the ballot for student body president, a student must turn in a petition with the signatures of 3% of the students. If there are 6,988 students, how many signatures must a student get to be on that ballot?