Chapter 1, Equations and Inequalities - Mixed Review of Problem Solving - Lessons 1.1-1.4 - Page 33,: 4

$16$

Let $x$ be the unknown term. Now, we will have to multiply $\$1.00$ and $\$1.80$ with the unknown term and we will add them both and set $\$45$ equal to the other side. This gives: $\$1.80x+\$1.00 x=\$ 45$ This implies that $\$2.80 x=\$45$ This yields: $x =\dfrac{2.80}{45} \ne 16.07$ Hence, we can conclude that we want to buy $16$ ground beefs and chicken.