## Thinking Mathematically (6th Edition)

(a) The difference is of $128\text{ billion dollars}$, and the budget was surplus. Consider the given bar graph. From the image above, the number corresponding to given year is, Money collected for 2001 was$1991$ billion dollars. Money spent for 2001 was$1863$ billion dollars. So, the total difference in amount is, $\left( \$1991\text{billion}-\$1863\text{billion}\right)=\$128\text{billion}$Thus, the difference is of$\text{128}\,\text{billion}\,\text{dollars}$. Since it is positive, the budget is surplus. (b) The difference is of$-1299\text{ billion dollars}$, and the budget was a deficit. Consider the given bar graph. From the image above, the number corresponding to given year is, Money collected in 2011 was$2034$billion dollars. Money spent in 2011 was$3603$billion dollars. So, the total difference in amount is,$\$2304\text{billion}-\$3603\text{billion}=-\$1299\text{billion}$ Thus, the difference is of$-\text{1299}\,\,\text{billion}\,\text{dollars}$. Since it is negative, the budget is a deficit. (c) The difference is of $1427\text{ billion dollars}$. Consider the given bar graph. From the calculations in previous parts, The surplus in $2001$was$128$ billion dollars The deficit in $2011$was$-1229$ billion dollars So, the total difference in amount is, \begin{align} & \text{Diff }=~128-\left( -1299 \right) \\ & =1427 \end{align} Thus, the difference is of$\text{1427}\,\,\text{billion}\,\text{dollars}$.