Answer: [tex]\$10,\ \$5[/tex]
Step-by-step explanation:
(a) Given
Sam charge $5 for each dog for a thirty minute walk
For an hour which is double the thirty minutes, it must be double of the same charge.
[tex]\Rightarrow 2\times 5=\$10[/tex]
(b)Given
With $20, Christie sells 100 cups of lemonade with a quarter per cup charge
For 100 cup, she generate a revenue of
[tex]\Rightarrow \dfrac{1}{4}\times 100\\\\\Rightarrow \$25[/tex]
So, she earns [tex]25-20=\$5[/tex] that is , her profit is [tex]\$5[/tex]