Question

8. A freight company charges a flat insurance fee to deliver a package anywhere in the continental United States, plus an additional charge for each pound the package weighs. The graph shows the relationship between the weight of the package and the total cost to ship it. Based on the graph, how much would it cost to ship a . 25-pound box?

(A) $37.00
(B) $48.00
(C) $62.50
(D) $74.50​

Answer 1

D 74.5

Explanation:

Solution 1:

Observing the graph we know that when weight is 0lb we need to pay a $12 flat fee.

When weight=2 lb we notice that the total cost would be $17.

Take out the flat fee:

17-12 = $5.

So, for every 2 lb we need to pay an extra $5; therefore for every lb we need to pay $2.5.

25lb * $2.5/lb = $62.5

Add flat fee: 62.5+12=$74.5

Solution 2:

use linear equation to solve the problem.

1. Find the equation of the graph.

- pick 2 pts (0,12) and (2, 17)

2. Set up equation:

`y=ax+b` and since the graph goes through (0,12)

thus
`y=ax+12`

3. plug in

- Plug in (2,17)

-
`17=2a+12` and
`a=2.5`

- so
`y=2.5x+12` where x is the weight and y is the total cost in dollar.

4. solve for x=25

`y=2.5*25+12=74.5`