<p>Student Produced Q: Chairs ready for shipment at the Northern Chair factory come down a ramp in single file. Inspector A checkes every third chair, beginning wiht the third. Inspector B checks every fifth chair, beginning with the fifth. If 98 chairs come down the ramp while both inspectors were working on Monday, how many of these chairs were NOT checked by either of these two inspectors?</p>
<p>The answer is 53, but I got 52..
Could anyone explain?</p>
<p>This is a sample SAT from the SAT booklet for the 2003-2004 SAT</p>
<p>Okay, well first you need to find out how many chairs the inspectors checked:
Inspector A: 98/3=32
Inspector B: 98/5=19</p>
<p>So, 32+19=51. However, there are overlapses because 5 and 3 are factors of 15, 30, 45, 60, 75, and 90. Therefore you need to subtract 6 from 51 to get 45.</p>
<p>The chairs that were NOT checked by inspectors comes out to be: 98-45= 53 </p>
<p>Hope this helps!</p>
<p>Yea, that's the same as I thought.</p>
<p>Got one of these wrong on the actual SAT
(Noticed the mistake, but heard "time's up" and I was sitting front row center during the SAT..)</p>