Unit 3, Lesson 11
Solving Problems about Percent Increase or Decrease
Accelerated 7
Sign in to view assessments and invite other educators
Sign in using your existing Kendall Hunt account. If you don’t have one, create an educator account.
Mai started a new exercise program. On the second day, she walked 5 minutes more than on the first day. On the third day, she walked for 42 minutes. This was a 20% increase from the second day.
Mai drew a diagram to show her progress.
Explain how the diagram represents the situation.
Three tape diagrams, day 1, day 2, day 3. Diagram Day 1, 1 part, labeled d. Diagram Day 2, 2 parts, first part, d, same length as d above, second part labeled 5. Diagram day 3, has 6 equal parts with no labels, The first five parts together are the length of the Day 3 diagram above, the total is 42.
Mai writes the equation
We can solve problems where there is a percent increase or decrease by using what we know about equations. For example, a camping store increases the price of a tent by 25%. A customer then uses a $10 coupon for the tent and pays $152.50. We can draw a diagram that shows first the 25% increase and then the $10 coupon.
Three tape diagrams of unequal length. Top diagram, original price, one part labeled p. Middle diagram, labeled 25% increase, 4 equal parts which total to the same length as p above, with another equal part on the end labeled point 25 p. Third diagram, same total length as diagram above, labeled 10 dollar coupon, first part labeled 152 point 50, second part, dotted outline, labeled 10.
The price after the 25% increase is
Help us improve by sharing suggestions or reporting issues.