Given the following information, find the fixed costs:

a. Total sales, $104,672; profit, $18,000; variable rate, .42

b. Profit, $12,000; number of customers, 32,392; variable cost per unit, $4.63; sales price per unit, $10.34

c. Sales price per unit, $14.60; profit, $34,000; number of customers, 26,712; variable rate, .35

d. Contribution rate, .65; sales price per unit, $18.40; number of customers, 26,549; profit, $33,000