Intermediate Algebra for College Students (7th Edition)

Published by Pearson
ISBN 10: 0-13417-894-7
ISBN 13: 978-0-13417-894-3

Chapter 1 - Section 1.1 - Algebraic Expressions, Real Numbers, and Interval Notation - Exercise Set - Page 14: 93


According to the formula, the percent of American adults who used smart phones to go online in $2013$ is 62%.

Work Step by Step

The calculated value underestimates the actual value by 1%. Consider $S=32+8.7x-0.3{{x}^{2}}$. Number of years from $2009$ to $2013$ = $4$years. So, put $x=4$in the given formula. $\Rightarrow S=32+8.7(4)-0.3{{(4)}^{2}}$ $\Rightarrow S=32+8.7\times 4-0.3\times 16$ $\Rightarrow S=32+34.8-4.8$ $\Rightarrow S=62\,%$ The actual percent shown in the bar graph is 63%, which is greater than the calculated value. Find the difference of both values. $=63percent-62percent\,\,=\,\,1percent$ So, the calculated value underestimates the actual value by 1%.
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