Question

These are the fees for sending a package by Media Mail:

Answer 1

First pound costs = $\verb# 2.41#$

Next 6 pound costs = $\verb# 0.41#$ * 6 = $\verb# 2.46#$

cost per additional pound is $\verb# 0.39#$ after 7 pounds.

Let x be the weight of package in pounds

additional pound is (x-7)

Cost of package = cost of 1 pound + cost of 6 pounds + cost of additional pounds

Given cost of package = 7.99

Cost =$2.41 + 2.46 + 0.39 (x-7)$

$7.99 = 2.41 + 2.46 + 0.39 (x-7)$

$7.99 = 4.87 + 0.39 (x-7)$

Subtract 4.87 on both sides

$3.12 = 0.39x - 2.73$

Add 2.73 on both sides

$5.85 = 0.39 x$

Divide by 0.39 on both sides

$x = 15$

The package weight 15 pounds