8.5 Problem Solving Using Percent You can use percents to solve real life problems, such as interpreting circle graphs or finding discounts.

Example In a survey conducted by a local newspaper, adults were asked how many hours per week they spent exercising. Suppose 18 adults said they spent 7 or more hours per week. Weekly Exercise Time 0 hours 45% 1-3 hr 33% 4-6 hours 17% 5% 7 or more hours

Example - continued How many adults were surveyed? Think…..What information do we have? 18 people said they exercised for 7+ hours. That is 5% of the total. How would that be written in the “is-of” statement? 18 is 5% of what number? 5 5

Example - continued How many adults said 0 hours? Again…what do we know? 45% said they exercised for 0 hours. There are a total of 360 adults How would that be written in the “is-of” statement? What number is 45% of 360?

Discount Last weekend you bought a jacket on sale for $ Today you are shopping in the same store and notice that the jacket is being sold at the regular price of $75. What was the discount percent you received last weekend? 75 75

Increase or Decrease A percent of increase or percent of decrease tells how much a quantity has changed. The percent of change of a quantity is given by

Examples 1995 profits - $235, profits - $455,000 Find the percent of increase members in 1996 – 422 members in 1997 – 394 Find the percent of decrease