In 2002, the price of mailing a letter was $0.34 for the first ounce or part of an ounce and $0.21 for each ounce or part of an ounce after the first ounce. How much did it cost to mail a four-ounce letter?
The equation would be .34 + .21(x -1) = C where x is the number of ounces and C = the cost. Let x = 4 to answer the question. .34 + .21(4-1) = C Do the work in the parentheses .34 + .21(3) = C multiply .34 + .63 = C Add .97 = C The cost to mail the letter is $0.97.