57. Maximizing Revenue Suppose the quantity demanded per week of a certain dress is related to the unit price \( p \) by the demand equation \( p = \sqrt { 800 - x } \) , where \( p \) is in dollars and
\( x \) is the number of dresses made. To maximize the revenue, how many dresses should be made and sold cach week? Hint \( R ( x ) = p x \) .
x=\(\frac{1600}{3}\)
Joe earns \( \$ 9 \) per hour. He worked \( x \) hours on both Wednesday and Friday, and \( 8 \) hours on both Tuesday and Saturday. Write an expression to represent how much Joe earned.
If a virus spreads at a rate that can be modeled by the exponential function \( A ( t ) = ae ^ { r t } \) , how many people will be infected after \( 5 \) days if initially \( 3 \) people are infected and the growth rate is \( 40 \% \) ?
