2. Real World Applications
Restaurant Tips
“While dining out 15%-20% is the
social norm for gratuity”
Test Grades
“Charlie received a 85% on his
last Math test”
Sales Tax
“In PA there is a 6% sales tax.”
3. PERCENT
is a ratio whose denominator is 100.
25%
The symbol for percent is %
is 25 “per hundred”
or
the fraction 25/100
4. This is one whole
square.
One
Whole
Square
Divide the square into
100 even pieces.
Everyone of
the 100 pieces
is shaded
So 100% of the square
is shaded orange.
So 100% and 1 Whole
are the same thing.
6. Now you try!
Write the percent as a fraction in simplest form
1. 51%
51 .
100
2. 25%
1
4
3. 80%
4
5
7. Fraction
Percent
Multiply numerator and denominator by the
same factor to make the denominator 100.
When in form p/100, then p is the percent.
Write 7/10 and 3/5 as a percent.
7 .×10 = 70 = 70% 3 .×20 = 60 = 60%
5 ×20 100
10 ×10 100
8. Now you try!
Write the fraction as a percent.
1. 11/20
2. 4/25
55%
16%
3. 5/100
5%
9. Writing Probability as a Percent
1. Find Probability and put into fraction form
2. Convert from fraction to percent
Prize: A radio station randomly selects 1 of 5 finalists for a prize.
You are one of the finalists. What is the probability that you will
win? Write your answer as a percent.
Solution: There are 5 possible outcomes, and 1 is favorable.
P(you win) =1/5 (write probability as a fraction)
= 20% (write fraction as a percent)
Answer: The probability that you will win is 20%.
10. Now you try!
A computer randomly generates an integer from 1 to 10. Find the probability of
the given event . Write your answer as a percent.
1. P(5)
2. P(odd #)
1/10 = 10 %
5/10 = 50 %
3. P(prime #)
5/10 = 50 %
11. Finding the percent of a number
1. Take percentage and convert to fraction
2. Put fraction in simplest form
3. Multiply fraction by Number
Tortoises: A desert tortoise can go a year or more
without drinking water. When it does drink, its body
weight can increase by 40%. Suppose a desert
tortoise weighs 15 pounds after a long period without
water. How many pounds can the tortoise gain when it
drinks.
2/
(15)
5
2/5
40/100
40%
6 pounds
12. Now you try!
Find the percent of a number.
1. 25% of 36
2. 70% of 70
9
49
13. SUMMARY
A percent is a ratio whose number is over
100
______ ?
Explain how you would re-write
13/25 as a percent.
You would multiply the numerator and denominator both by
4.Then you would get 52/100. 52% would be your answer.
14.
15. Name: __________________________
Date: _________________
Directions: Please complete each section and circle your final answer. Show your wo
Percents to
Fractions
Fractions to
Percents
Writing Probability
as a Percent.
Finding the
percent of a
number.
Round to nearest tenth.
1. 36%
1. 1/5
A computer randomly
generates and integer
from 1-5
1. 60% of 12
1. P(4)
2. 3%
2. 2/5
1. 15% of 100
2. P(odd)
3. 90%
3. 4/100
3. P(a number
divisible by 2)
1. 50%
1. 8/25
4. P(prime #)
2. 30% of 300
1. 50% of 400
