Chapter 6.4, Problem 18IP

To determine

To find: Percent error.

Answer to Problem 18IP

Percent error is $-50\%$

Explanation of Solution

Given information:

Estimated time $=40$ workdays

Actual time $=80$ workdays.

Percent error $=\frac{A}{O}\times 100$

Where

  $A=$ Absolute value.

  $O=$ Actual value.

From given information

Estimated time $=40$ workdays

Actual time $=80$ workdays.

Absolute value = Estimated value $-$ Actual value.

  $\begin{array}{l}\Rightarrow A=40-80\\ \Rightarrow A=-40\end{array}$

Therefore,

Percent error $=\frac{-40}{80}\times 100$

  $\Rightarrow$ Percent error $=\frac{-4000}{80}$

  $\Rightarrow$ Percent error $=-50$

So, Percent error is $-50\%$ .