Chapter 6
6.5 – Percent of Change
Objective…
Part A: Solve word problems involving percent increase and decrease
1)
Mr. Sato sells fish at a 60% markup. He pays $3.75 per pound for
haddock one week. At what price per pound will he sell it?
2)
At a post office, the weight of the mail at 10 am was 80 pounds.
Two hours later, the weight of the mail had increase by 30%. Find
the weight of the mail at noon.
3)
The price of a new car was $22,800 in April. However, the price
of the car was reduced by 5% in May. Find the price in May.
Chapter 6
6.5 – Percent of Change
Part B: Solve word problems by finding a quantity represented by a percent.
1)
William had a length of brass chain. He used 30% of the chain to
make some necklaces. The remaining length of the brass chain was
385 centimeters long. He then used 25% of the remaining chain to
make some key chains.
a. What was the original length of the brass chain?
b. What was the remaining length of the brass chain after making
the key chains?
2)
One Friday, a restaurant received enough orange juice for a week.
After the weekend, the restaurant’s orange juice supply had
decreased by 24% to 76 quarts. After Monday, the supply had
further decreased by 20%.
a. What was the original amount of orange juice received?
b. How much orange juice was left after Monday?
Chapter 6
6.5 – Percent of Change
Part C: Find percent increase or decrease to solve word problems
1)
The regular price of a Statue of Liberty souvenir was $32. During
a sale, its price was reduced to $24. Find the percent discount.
2)
Dennis bought an antique model train for $64. Two years later, he
sold it for $72. What was the percent increase in the price of the
model train?
3)
The original length of a spring was 28 millimeters. It was
stretched to a length of 35 millimeters. Find the percent increase
in its length.
Chapter 6
6.5 – Percent of Change
Part D: Find percent increase or decrease to solve multi-step problems
1)
The original price of a book in 2003 was $12. In 2005, the price of
the same book increased to $15. In 2007, the price of the book
was $3 more than the price of the book in 2005.
a. Find the percent increase in the price of the book from 2003 to
2005.
b. Find the percent increase in the price of the book fro 2005 to
2007.
2)
The amount of the water in a dispenser was 50 liters at first.
After 10 minutes, it decreased to 45 liters. Another 15 minutes
later, the amount of water had decreased to 40 liters.
a. Find the percent decrease in the amount of water the first 10
minutes.
b. What was the percent decrease in the amount of water from 45
liters to 40 liters?
Chapter 6
6.5 – Percent of Change
Part E: Solve word problems involving fractions and percents
1)
One year, Keith’s savings was $200. Andrew’s savings was 4/5 of
Keith’s savings. The next year, Andrew increased his savings by
20%. Find the increase in Andrew’s savings.
2)
On Monday, Camille scored 120 points in a video game and Emily
scored 5/4 as many points as Camille. On Tuesday, Emily scored
30% more points than what she scored on Monday. Find the
increase in the number of points Emily scored on Tuesday.