Chapter 7.5, Problem 9E

To determine

To calculate:To find the percent of change.

Answer to Problem 9E

Percent decrease = $40\%$

Explanation of Solution

Given information:

Consider the information provided in the question, Original: $45$ and New: $72$

Formula used:

  $\text{percent of change, }p\text{\% =}\frac{\text{Amount of increrase or decrease}}{\text{Original amount}}$

Calculation:

It is observed that there is increase in percent,

  $\begin{array}{l}\text{percent of change, }p\text{\% =}\frac{\text{Amount of increrase or decrease}}{\text{Original amount}}\\ \text{ = }\frac{\text{Amount of increase}}{\text{Original Amount}}\text{ [write formula for percent of decrease]}\\ \text{ = }\frac{70-42}{70}\text{ [substitute]}\\ \text{ = }\frac{28}{70}\text{ [subtract]}\\ \text{ = 0}\text{.4}=40\%\text{ [divide}\text{. Then write decimal as a percent] }\end{array}$

Therefore, Percent of increase = $40\%$