91Ó°ÊÓ

Clark's rule is "Multiply the adult dose with the weight of the child (in pounds) and divide by 150 (the average weight of an adult)." Assign the variables and write a formula that describes Clark's rule.

Fried's rule for infants is "Divide the age in months by 150 and multiply it by the adult dose." Assign the variables and write a formula that describes Fried's rule.

Problem: Complete the "Understand the problem," "Make a plan," and "Complete the plan" steps. The regular price of a 12 -cup programmable coffee maker is \(\$ 79.99\). The sale price is \(\$ 59.99\). Find the percent discount. Round to the nearest percent. Incorrect Answer: The unknown is the percent discount; \(P=\) percent discount. A word equation is percent decrease \(=\left(\frac{\text { decrease in price }}{\text { sale price }}\right)(100) \%\). $$ \begin{aligned} &P=\left(\frac{\$ 79.99-\$ 59.99}{\$ 59.99}\right)(100) \% \\ &P=33 \% \text { decrease } \end{aligned} $$

\(\frac{15-3^{2}}{2+4}\)

\((-5)^{2}\)

\(8^{2} \div 4-12(2-7)\)

The shape of a table top is a trapezoid with bases that measure \(25 \mathrm{in}\). and \(60 \mathrm{in}\). The height is \(30 \mathrm{in}\). Find the area of this table.

Roofing shingles are sold by the "square." A square can cover an area of roof that is \(10 \mathrm{ft}\) long and \(10 \mathrm{ft}\) wide. The area of a roof is \(3450 \mathrm{ft}^{2}\). Find the number of squares of roofing shingles needed to cover this roof. Round up to the nearest whole number.

\(\frac{3^{2}-5 \cdot 9}{-6^{2}}\)

Problem: Find the simple interest earned on \(\$ 300\) invested for 5 years at an annual simple interest rate of \(4.5 \%\). Incorrect Answer: \(I=P R T\) $$ \begin{aligned} &I=(\$ 300)\left(\frac{4.5}{1 \text { year }}\right)(5 \text { years }) \\ &I=\$ 6750 \end{aligned} $$