the total cost of mailing a letter is expressed by : 0.42 + (0.17w)
the cost of mailing a four ounces letter is $1.10
step by step explanation:
first, you have a fixed cost, independent of any other variable, which is: 0.42.
then you have a cost that is independent on the weight. expressed the ounces, which is: 0.17 per ounce. that means if you have 2 ounces then your cost would be duplicated, becoming 0.34 and so on forth, let’s define the weight as w.
the total cost of mailing a letter equals the base charge or the fixed cost. plus the cost of the number of ounces that our letter weighs.
we can express this statement in a mathematics terms:
0.42 + ( 0.17 * w) = COST
now, we want to know how much it would cost us to mail a letter that weighs 4 ounces. that means we know the value of the “w” in our expression, so we can substitute it and solve the expression:
0.42 + (0.17 * 4 ) = COST
0.42 + 0.68 = COST
1.1 = COST
it would cost us $1.10 to send a 4 ounces letter :)