The best answer to go with is b
D1 = 60 for a price of $80. Charging $80 will ensure supply exceeds demand.
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The store apparently could charge a price slightly lower than $80, but we cannot tell from the chart how much lower.
Answer:
x + y = 13
98x + 115y = z
Step-by-step explanation:
Let x represent the time spent taking class in Westside community college
Let y represent the time spent taking class in Pinewood community college
Let z represent the combined total amount paid for the class fees.
The total combined time for the two school is given as:
x + y = 13.
For the combined total amount; we multiply the price for each school with the time spent on the school and sum them together.
Westside: 
Pinewood: 
The combined total amount represented as z is given as:
z = 98x + 115y