<p>11 Which of the following could be the exact value of n^4 where n is an integer?</p>
<p>(A) 1.6 x 10^20
(B) 1.6 x 10^21
(C) 1.6 x 10^22
(D) 1.6 x 10^23
(E) 1.6 x 10^24</p>
<p>Someone please explain this, I don't get it at all!</p>
<p>The answer is B. Just plug each number into the equation x^(1/4). B comes out to be 200,000 and is the only answer which gives you an integer number.</p>
<p>Could you show the work or something. I’m still not understanding.</p>
<p>Since 2^4 = 16, the number n is : 2 x 10^cabbage, where “cabbage” is an integer. Then, (2 x 10^cabbage)^4 = 16 x 10^(4 x cabbage) = 1.6 x 10^(4 x cabbage + 1).</p>
<p>Only answer B has a power of 10 in the form 4 x cabbage + 1 (namely, cabbage=5).</p>
<p>A good pre-calculator SAT problem. The above solution is probably the easiest, given a calculator.</p>
<p>Thanks fig, I get it now!</p>
<p>1.6=16 times 10 ^20. 16 and 20 both divide by 4 to give an integer;it’s the only answer that works.</p>
<p>^
Actually, it’s not that 16 is divisble by 4…it’s that 16 has an integer value for its 4th root.</p>
<p>And it IS that 20 is divisible by 4 because that means that 10^20 has an integer value for its 4th root as well.</p>