Identify the following costs as fixed or variable: Costs related to plane trips between Boston, Massachusetts, and San Diego, California, follow. Pilots are paid on a per-trip basis.
a. Pilots’ salaries relative to the number of trips flown.
b. Depreciation relative to the number of planes in service.
c. Cost of refreshments relative to the number of passengers.
d. Pilots’ salaries relative to the number of passengers on a particular trip.
e. Cost of a maintenance check relative to the number of passengers on a particular trip.
f. Fuel costs relative to the number of trips.

In simple words, fixed cost refers to the cost that remain stable every time whereas the variable cost are the costs that changes with every change in the level of operations. Thus, the given expenditures can be categorized as follows :

1. Variable cost

2. Fixed costs

3. Variable costs

4. Fixed cost

5. Fixed cost

6. Variable cost

answerpounds of plastic to purchase 200+60-20=(240);

of the three mortgage options that demarco and tanya have to choose from, the balloon payment mortgage would be their best option, over adjustable payment and fixed payment plans.ultimately, the balloon payment plan would save demarco and tanya overall, in interest, would cost less monthly, and they would only have to make these payments for 8 years, opposing to 30 years for adjustable or fixed payment plans. 

overall, demarco and tanya would save $80,811 if they chose balloon payments over fixed payments, and would save $116,711 if they choose balloon payments over adjustable payments. benefits with choosing fixed payments over adjustable payments is that, in the end, the payments will still be $836.30 a month, while with adjustable payments, the initial monthly payments will be $763.38 to $1082.70 a month, ultimately leading to a more costly purchase. benefits with choosing fixed payments over balloon payments are not present. benefits in choosing adjustable payments over is that it has a lower interest rate, and starts with lower monthly payments initially. benefits in choosing adjustable payments over balloon payments include a lower interest rate, and lower initial monthly payments. benefits in choosing balloon payments over fixed payments include lower interest rates, lower overall price, lower monthly payments, takes less time to pay off, and does not require a downpayment. benefits in choosing balloon payments over adjustable payments include, lower monthly payments (when averaged), takes less time to pay off, and lower overall price.

hence, option c, balloon payments, is the best option for demarco and tanya to make this purchase, for it will save them a minimum of $80811, and a maximum of $116,711.