Exercise 65 Page 472

To determine percent change p, we can use the following general formula. p % =Amount of increase or decrease/Original amountFrom the given values, we can see the original amount was $40 and the new amount is $70. This is an increase in the amount. $70- $40= $30 The difference between the new amount and the original amount is $0. Now we can use the formula.

Percent change=Amount of increase/Original amount

SubstituteValues

Substitute values

Percent change=$30/$40

ReduceFrac

a/b=.a /30./.b /30.

Percent change=3/4

UseCalc

Use a calculator

Percent change=0.75

WritePercent

Convert to percent

Percent change = 75 %

The percent increase is 75 %.