Chapter 3.5
PERCENTS AND THEIR
APPLICATIONS
Copyright © 2014 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill/Irwin
Begin Here
2
A roof is expected to last 12 years before it needs
replacement. If the roof is 10 years old, what percent of the
roofs life remains
% 12 = 2
% = 1/6 = 16.7%
3
The price of a home sold by an agent
This year is $187,000 which is 10% more
than last year’s value. Find the value last
year.
This is a Rate*Base=Part
The rate associated with this year is 110%
The base is the last years value is: B
110% B = 187000 or B=187,000/1.1
= 170,000 [NOT!! .9*187000=168,300]
4
Sales of ICON’s devise have grown by by
20% per year for each of the past 2
years. $93,600 are sold this year.
What was base sales one year ago?
rate is 120%
Rate * Base = 93,600
120% * Base = 93,600
Base = 93,600/1.2= 78,000
5
What was the sales 2 years ago:
Rate * Base = $78000 = sales
one year ago
120% *Base = $78000
Base= 78000/1.2= $65,000
6
The rate of increase from 2 years
ago is: 120%2= 1.22= 1.44
So Rate*Base = 93000
