Refer to the accompanying table to answer the questions. $$\begin{array} { | l | c | c | }
\hline \begin{array} { l }
\text { Price of } \
\text { Erasers }
\end{array} & \begin{array} { l }
\text { Quantity } \
\text { Demanded of } \
\text { Erasers }
\end{array} & \begin{array} { l }
\text { Quantity } \
\text { Demanded of } \
\text { Pencils }
\end{array} \
\hline \$ .50 & 10 & 12 \
\hline \$ 1.00 & 8 & 11 \
\hline \$ 1.50 & 7 & 10 \
\hline \$ 2.00 & 6 & 9 \
\hline \$ 2.50 & 5 & 8 \
\hline
\end{array}$$
-The price of erasers increases from $0.50 to $1.00 per eraser. By what percentage does the quantity demanded of pencils change? (Use the midpoint method.)
A) 8.70%
B) 22.22%
C) -22.22%
D) -8.70%
E) 6.67%

Question

Refer to the accompanying table to answer the  questions. $$\begin{array} { | l | c | c | } 
\hline \begin{array} { l } 
\text { Price of } \
\text { Erasers }
\end{array} & \begin{array} { l } 
\text { Quantity } \
\text { Demanded of } \
\text { Erasers }
\end{array} & \begin{array} { l } 
\text { Quantity } \
\text { Demanded of } \
\text { Pencils }
\end{array} \
\hline \$ .50 & 10 & 12 \
\hline \$ 1.00 & 8 & 11 \
\hline \$ 1.50 & 7 & 10 \
\hline \$ 2.00 & 6 & 9 \
\hline \$ 2.50 & 5 & 8 \
\hline
\end{array}$$
-The price of erasers increases from $0.50 to $1.00 per eraser. By what percentage does the quantity demanded of pencils change? (Use the midpoint method.)
A) 8.70%
B) 22.22%
C) -22.22%
D) -8.70%
E) 6.67%

Quizplus · Accepted Answer

Using the midpoint method, the percentage change in quantity demanded of pencils is calculated as $\frac{(11 - 12)}{(11 + 12)/2} \times 100 = -8.70\%$.

Refer to the Accompanying Table to Answer the Questions