Notes~~~Percent of Change: Increase or Decrese
A percent of change can be expressed using direct variation: y=kx
y=- new pricek= percent of changex = origianl price
Example:
$15.60 to $11.70 this is a decrease
y=kxy=11.70 (new)k=percent changex = 15.6 (original)
11.7 = 15.6xdivide both sides by 15.6 and
x = .75 move the decimal to make a percent 75% and then subtract from 100% and you get as an answer A DECREASE OF 25%
Example:
$8 TO $12 this is an increase
y= kxy = 12 (new)k= percent chancex = 8(original)
12 = 8xdivide both sides by 8 and
x = 1.5 move the decimal to make a percent 150% and then subtract from 100% and you get as an answer A INCREASE OF 50%
Example:
$35 TO $28 this is an decrease
y= kxy = 28 (new)k= percent chancex = 35(original)
28 = 35xdivide both sides by 35 and
x = 0.8 move the decimal to make a percent 80% and then subtract from 100% and you get as an answer A DECREASE OF 20%
1. A popular brand of running shoes costs a local store $68 for each pair. If the store sells the shoes for$119, what is the percent of increase in the price?
2. Last year the backgammon club had 30 members. This year the club has 24 members. Find the percent of decrease in the number of members.
3. When Ricardo was 9 years old, he was 56 inches tall. Ricardo is now 12 years old and he is 62 inches tall. Find the percent of increase in Ricardo's height to the nearesttenth.
4. The 2008 yearbook at Middleton Middle School had 236 candid pictures of students. The 2007 yearbook had 214 candid pictures of students. What was the percent of change in the number of candid student pictures from 2007 to 2008 to the nearest tenth?
Find each percent of change. Round to the nearest whole percent if necessary. State whether the percent of change is an increase or a decrease.
4. $65 to $755. 500 albums to 100 albums
6. 3.25 meters to 2.95 meters7. 464 kilograms to 20 kilograms
9. 16 minutes to 24 minutes10. 24 hours to 86 hours