<p><span style="color:#8e44ad;"><span style="font-size:20px;">Deductions from the Given Information</span></span></p>
<p>There's quite a bit to read here, so it's a good idea to go <strong><span style="color:#8e44ad;">Piece by Piece</span></strong> to make sure we don't miss anything.</p>
<blockquote>
<p>The list price of a certain tool is x dollars.</p>
</blockquote>
<p>The list price of the tool is $x$</p>
<blockquote>
<p>In Store A the original selling price of the tool was S50 less than the list price,</p>
</blockquote>
<p>The original selling price of the tool in Store A is $x - 50$</p>
<blockquote>
<p>and the current selling price is IO percent less than the original selling price.</p>
</blockquote>
<p>The current selling price of the tool in Store A is $0.9 * original\,selling\,price = 0.9 * (x-50) = 0.9x - 45$</p>
<blockquote>
<p>In Store B the original selling price of the tool was IO percent less than the list price,</p>
</blockquote>
<p>The original selling price of the tool in Store B is $0.9 * list\,price = 0.9x$</p>
<blockquote>
<p>and the current selling price is $50 less than the original selling price.</p>
</blockquote>
<p>The current selling price of the tool in Store B is $original\,listing\,price - 50 = 0.9x - 50$</p>
<p><span style="color:#27ae60;"><span style="font-size:20px;">Solving the Problem</span></span></p>
<p>We are asked to compare the current SELLING price of the tool in both stores. This would be:</p>
<p>$0.9x - 45$ vs $0.9x - 50$</p>
<p>We can <strong><span style="color:#8e44ad;">Manipulate</span></strong> these by taking away $0.9x$ from both sides:</p>
<p>$-45$ vs $-50$</p>
<p>Now, we can add $50$ to both sides:</p>
<p>$5$ vs $0$</p>
<p>Since $5$ is clearly bigger than $0$, QA would be bigger.</p>
<p>So, the answer should be <span style="color:#27ae60;">A</span>. </p>
<p> </p>