Answers:
A) The profit function is P(x) = 1.50x - 90 where P is the profit and x is the number of bags sold
B) You must sell 60 bags to break even.
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Step-by-step explanation:
x = number of bags sold
1.50*x = 1.50x = revenue earned from selling x bags at $1.50 a bag
The revenue is the amount of money you earn. The cost is 90 which is subtracted off the revenue to get the profit, so P(x) = 1.50x - 90 is the profit function.
The breakeven point happens when the profit P is 0. Replace P(x) with 0 and solve for x
P(x) = 1.50x - 90
1.50x - 90 = P
1.50x - 90 = 0 ... replace P with 0
1.50x = 90 ... add 90 to both sides
x = 90/1.50 ... divide both sides by 1.50
x = 60
If you sold 60 bags of popcorn, then you will break even. This is where the profit is $0. You do not make any money, nor do you lose any money. If you sell more than 60 bags, then the profit will be some positive number.