
The package would cost $56.25. Great work if you found that price. This price

also makes sense, since our package weighs more and it's longer in length. So it

should definitely cost more than $20 to ship. We want to start by setting up a

proportion that has direct variation. The cost varies directly with the length.

And the cost varies directly with the weight. The next thing that we want to do

is make a list of the things we know. We know the first cost was $20.00, the

length was four feet, and it measured 10 pounds. Next we fill in the proportion

with the remaining pieces. The second cost, the second length, and the second

weight of the package. We make a list of those amounts as well. We're looking

for the cost of our package, so that's going to be x. The length of that package

is seven and a half feet. And the weight of that package is 15 pounds. Now we're

ready to fill in our proportion. Plugging in these amounts into our proportion,

we get this equation. I'm going to clean up the right hand side of my equation

first. Four times ten is 40. And 7.5 times 15 is 112.5. So I've written this

cleaned up part over here. Next we cross multiply to get 2,250 equals 40x and

finally we divide both sides by 40 to get our final answer.