Suppose a postal service charges $10.30 per pound on a package shipped to England.What is this rate in dollars per ounce?

Answer 1

There is one conversion we must make in this problem, which is pounds to ounces. To do so we need to cancel out the units of pounds and replace them with ounces. There are 16 oz / lb

Setting up the problem:

= [10.30 (dollars) / 1 (pound) ] x [1 (pound) / 16 (ounces)]

= [10.30 (dollars) x 1 (pound)] / [1 (pound) x 16 (ounces)]

= 10.30 (dollars) / 16 (ounces)

= 0.6438 (dollars) / 1 (ounce)

By orienting our division such that the units of (pound) cancel each other, we are left with 0.6438 dollars per ounce.