Question

The rate for mailing an envelope is $0.80 per ounce. Choose a function rule that represents the total cost, c(w), to mail an envelope weighing w ounces. How much will it cost to mail an envelope that weighs 5 ounces?

Answer 1

$0.80 per ounce.

for w ounces, cost will be: 0.80*w = 0.80w

Therefore c(w) = 0.80w

The cost for 5 ounces = 0.80*5 = 4.00

Cost for 5 ounces = $4.00

Hope this helps.

Answer 2

Answer: c(w) = 0.80 w and the cost of 5 ounces is $4

Explanation:

To solve this we can simply use proportionality

from the question,

$0.80 = 1 ounce

c(w) = w

cross multiply

c(w) = $0.80 w

Therefore a function rule that represents the cost c(w) is $0.80 w

For the second part of the question, we are to find the cost of an envelope that weighs 5 ounce

we have different way of doing this, the first of which is to just use our function rule;

c(w) = $0.80 w

we substitute w= 5 into the function. Hence;

c(5) = $0.80 × 5 = $4

OR

We can use a longer method;

let x = the cost of 5 ounces

$0.80 = 1 ounce

x = 5 ounces

cross multi[ply

x = $0.80 × 5 = $4

Therefore, the cost of mailing an envelope that weighs 5 ounces is $4.