Unit 6, Lesson 15
Functions Involving Percent Change
Algebra 1
Practice
Problem 1
In 2011, the population of deer in a forest was 650.
- In 2012, the population increases by 15%. Write an expression, using only multiplication, that represents the deer population in 2012.
- In 2013, the population increases again by 15%. Write an expression that represents the deer population in 2013.
- If the deer population continues to increase by 15% each year, write an expression that represents the deer population \(t\) years after 2011.
Problem 2
Mai and Elena are shopping for back-to-school clothes. They found a skirt that originally cost \$30 on a 15%-off sale rack. Today, the store is offering an additional 15% off. To find the new price of the skirt, in dollars, Mai says they need to calculate \(30\boldcdot 0.85\boldcdot 0.85\). Elena says they can just multiply \(30\boldcdot 0.70\).
- How much will the skirt cost using Mai’s method?
- How much will the skirt cost using Elena’s method?
- Explain why the expressions used by Mai and Elena give different prices for the skirt. Which method is correct?