The cost(C) in $ of catering per head in a restaurant with the number (N) of people present is given by C = a + b
N If the cost per head for 10 people is $14 and the cost per head for 20 people is $12, find (to the nearest 10c) the cost per head for 50 people

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Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?

Nick and nora are married and have three children in college. they have an adjusted gross income of 47,400. if their standard deduction is 12,600 itemized deductions are 14,200 and they get an exemption of 4000 for each adult and each dependent what is their taxable income