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Here’s a shmoopy question for you… Unlike his shady friend Dishonest Paul, Honest
John actually pays for songs from iTunes. He pays for x number of songs at a total
cost of $12.50. At this rate, what is the total cost of 10
songs? Here are the potential answers:
Before we spoil the ending, hit pause and try it yourself.
OK, this question is testing whether we know the business formula for cost…
…or a fancy way of asking us to calculate the unit price times a quantity.
The formula looks like this:
Price times quantity equals total cost. Well, we know the base elements here:
Price times x number of songs equals $12.50. So we can set up the equation… px equals
12.5.
We should isolate p in the equation because we'll want to use p later to find the total
cost of 10 songs...or 10p.
To isolate p, we can divide p from both sides of the equation... getting p equals 12.5 over
x. Remembering that we want to find 10p... we
can multiply 10 times 12.5 over x to get 125 over x.
It looks like our answer is B.
Of course, if your name is Dishonest Paul, you already knew that.