of the increase or decrease is used as the part. For example, suppose a
calculator sold for $40 last week and is on sale for $30 this week. The
decrease is $40$30¼$10. The percent of decrease is^1040 ¼0.25 or 25%.EXAMPLE:The price of a textbook increased from $60 to $75. Find the
percent increase in the price.SOLUTION:GOAL: You are being asked to find the percent of the increase in price.STRATEGY: Find the increase, and then place that number in the top
portion of the circle. The base is the original cost. UseR¼PB. See Figure 5-6.IMPLEMENTATION: The increase is $75$60¼$15.R¼P
B
R¼
15
60
¼
15
60
¼ 0 : 25 ¼ 25 %
Hence, the rate of increase is 25%.EVALUATION: Find 25% of 60: 0.25$60¼$15. The solution is correct.Fig. 5-6.48 LESSON 5 Using Percents