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Percentage word problems



Before you learn about percentage word problems, review Formula for percentage or you can use the approach that I use here.

Example #1:


A test has 20 questions. If peter gets 80% correct, how many questions did peter missed?

The number of correct answers is 80% of 20 or 80/100 × 20

80/100 × 20 = 0.80 × 20 = 16

Recall that 16 is called the percentage. It is the answer you get when you take the percent of a number

Since the test has 20 questions and he got 16 correct answers, the number of questions he missed is 20 − 16 = 4

Peter missed 4 questions



Example #2:


In a school, 25 % of the teachers teach basic math. If there are 50 basic math teachers, how many teachers are there in the school?

I shall help you reason the problem out:

When we say that 25 % of the teachers teach basic math, we mean 25% of all teachers in the school equal number of teachers teaching basic math

Since we don't know how many teachers there are in the school, we replace this with x or a blank

However, we know that the number of teachers teaching basic or the percentage = 50

Putting it all together, we get the following equation:

25% of ____ = 50 or 25% × ___ = 50 or 0.25 × ____ = 50

Thus, the question is 0.25 times what gives me 50

A simple division of 50 by 0.25 will get you the answer

50/0.25 = 200

Therefore, we have 200 teachers in the school

In fact, 0.25 × 200 = 50



Example #3:


24 students in a class took an algebra test. If 18 students passed the test, what percent do not pass?

Set up the problem like this:

First, find out how many student did not pass.

Number of students who did not pass is 24 − 18 = 6

Then, write down the following equation:

x% of 24 = 6 or x% times 24 = 6

To get x%, just divide 6 by 24

6/24 = 0.25 = 25/100 = 25%

Therefore, 25% of students did not pass

If you really understand the percentage word problems above, you can solve any other similar percentage word problems.

If you still do not understand them, I strongly encourage you to study them again and again until you get it. The end result will be very rewarding!




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