We know that 40% of the class are girls because 60% are boys. To express 40% as a fraction of the 25 total students, we set up a proportion to find the number of girls in the class. 

When solving for , we find that there are 10 girls in the class. 

You can think of the total number of students in the classroom as an unknown variable, .

You can set up an equation that includes  and the information given. Normally in a percent problem, you would start with the total amount of something and multiply it by the percent to get the part of that total amount. You can set this up the same way, but the total amount is the missing information:

Total Amount x Percent = Part of Total Amount

You use  to numerically represent 15 percent. 

Now you can algebraically solve for , which will give you the total number of students in the class. You do this by dividing each side by .

Therefore there are 60 total students.

First we need to get  and 35% in the same terms so that we can subtract one from the other. Since 7ths are repeating decimals, it will be easiest to use fractions.

.

Now we multiply this fraction by 2.8 million, which reduces nicely to , which equals 180,000.

In order to solve this problem, you must first solve for what percentage of the entire group comprise of Spanish-speaking students. To do this, divide the total amount of Spanish-speaking students by the total number of students.

Multiply this number by 100 and round up in order to get your percentage.

Then, multiply this number times the total degrees in a circle to find out the measurement of the piece representing Spanish-speaking students on the pie chart.

Round up:

The meaning of a percent is the number over 100 parts.

When dividing  by , the reduced form is:

 is the equivalent of  percent, which is therefore the correct answer.

The percentage of students who attended the field trip can be found by dividing the number present by the total number of students.  Here this is  divided by .  You then multiply by  to get the percentage.

Annie needs the signatures of 5% of the 412 seniors; this is

,

which means she needs the signatures of at least 21 seniors. She has 22.

She needs the signatures of 5% of the 436 juniors; this is

,

which means she needs the signatures of at least 22 juniors. She has 23.

She needs the signatures of 5% of the 536 sophomores; this is

.

which means she needs the signatures of at least 27 sophomores. She has 26.

She has enough signatures from seniors and juniors, but not sophomores.

At the very least, Rhonda won 60% of the votes cast, so the total number of votes won by her opponents can be at most 40% of the votes cast. Suppose this is the case. If we let be the number of votes Rhonda won, then we can set up the ratio

At minimum, Rhonda won 324 votes.

Carla and Lisa won the highest and second-highest number of votes, respectively, so Hy must  have won fewer votes than Lisa. He won at most 65 votes. This would have been

The closest answer is 25%.