Answer: 
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.
(b)Given
With $20, Christie sells 100 cups of lemonade with a quarter per cup charge
For 100 cup, she generate a revenue of
So, she earns 
that is , her profit is 
The doctor had the opinion about the boy that it world
hare been better is he had velict
A -120 difference will be seen in the temperature within a 7 hour period
<u>Equation</u>
<em>-</em>30 x 7
<em>Multiplying two of different signs ( - + , + - ) will always be negative.</em>
<em>Multiplying two of the same sign ( - - , + + ) will always be positive.</em>
Looking for the height, if trapezoid area equals (a+b)/2 x h then h = 2A/(a+b)
so h = 2(30)/(4.8+5.2) = 6
