Percentage word problems
Before you learn about percentage word problems, review Formula for percentage
or you can use the approach that I use here.
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
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
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!
Sep 01, 18 04:07 PM
These heart of algebra questions will help you prepare to take the math portion of the SAT
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