Christine L. answered • 12/10/14

Tutor

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UCB Grad & HS Teacher: HS/College Subjects, Math, Test Prep, etc

Let x = pounds after the first pound = additional pounds

Set your equations to be equal.

5 + 0.3x = 7 + 0.2x

Isolate x.

5-7 = 0.2x-0.3x

Simplify.

-2 = -0.1x

Solve for x.

x= -2/-.1

x=20 lbs

Plug back in to get price.

$5 + $0.3/lb * 20lb = $5 + $6 = $11

Remember, x = additional pounds = number of pounds AFTER the first pound (meaning total pounds shipped = x+1 = 21lbs)

So, when you ship 21 pounds, you will pay $11 at either place.