<p>Practice test #2 Section 3 Number 18
page 463</p>
<p>the answer explanation online isn't really clear on it... can anyone explain the problem and why the answer is A to me?</p>
<p>Ok, this is quite simple actually.
To state the obvious parts first:</p>
<p>x = amount of dollars 1st shirt
Since we have additional shirts, we have the x-z dollars.</p>
<p>x + (x-z)</p>
<p>Then, we know that n = amount of shirts
However, because of counting problems, we must place (n-1), in order to get the right cost. Therefore it must be:</p>
<p>x + (n-1)(x-z)</p>
<p>Think of it this way, if you are buying two shirts, you MUST put n-1, otherwise:</p>
<p>x + 2(x-z)</p>
<p>You would get the cost of 3 shirts. Remember that x represents the cost of the 1st shirt. </p>
<p>Hope that makes sense.</p>
<p>The answer is A</p>