<p>Which of the following fractions is equal to 1/(11)^20-1/(11)^21?</p>
<p>the answer is 10/(11)^21</p>
<p>How do you do this problem???</p>
<p>Thanks!</p>
<p>Factor:</p>
<p>(1/11)^20 (1 - 1/11)</p>
<p>= (10/11)(1/11)^20</p>
<p>= 10/(11^21)</p>
<p>i totally see that now but I would never have thought to do that…ugh…How would I know to do that? this was the only one I had a problem with…just couldn’t see it. thanks!</p>
<p>Just think to yourself, “Both fractions have 1/11 raised to some power. Maybe I should factor!”</p>
<p>gottacha. makes perfect sense…that’s why you are at MIT???</p>
<p>Well, a 36 on the ACT math doesn’t gain acceptance into MIT. But I’ve held a lot of other math awards/honors (qualified to USAMO, perfect score on AMC10, 1st/2nd in some regional/state competitions, etc.).</p>