Transcript Percent Increase and Percent Decrease

Percent Increase
and Percent Decrease
Percent of Change
A PERCENT OF CHANGE is
the percent a quantity increases
or decreases from its
ORIGINAL amount.
Steps to Solve:
•
Example #1
• Problem: Last year, a school had 632
students. This year the school as 670
students. Find the percent of
increase in the number of students.
• Solution:
a) Find the amount of change.
b) Place the values in the ratio.
c) Divide.
d) Move 2 places to the right (x100).
Example #2
• Problem: Find the percent markup
for a car that a dealer buys for
$10,590 and sells for $13,775.
• Solution:
a) Find the amount of change.
b) Place the values in the ratio.
c) Divide.
d) Move 2 places to the right (x100).
Example #3
•Problem: Find the percent of
discount for a $74.99 tent that is
on sale for $48.75.
•Solution:
a)
b)
c)
d)
Find the amount of change.
Place the values in the ratio.
Divide.
Move 2 places to the right (x100).
Example #4
• Problem: The
number of students
enrolled in a school
has increased from
1,938 to 2,128. A
student calculates the
percent of increase.
His work is shown.
Explain the student’s
mistake and find the
correct answer.
Example #5
• Problem: A
football player
gained 1,200 yards
last season and 900
yards this season.
Find the percent of
change. State
whether the change
is an increase or
decrease.
Example #6
Problem: In a previous
game the school’s star
basketball player scored
25 points. In today’s
game he scored 40
points. What was the
percent of change in the
player’s scoring? Is the
change an increase or
decrease?