<p>Explaining modern art is impossible, partly because of its complexity but largely because {of it rapidly changing}.</p>
<p>(A) of it rapidly changing
(C) of the rapidity with which it changes</p>
<p>The answer given is C; I understand why, but why can't A be correct??? C seems a bit wordy.</p>
<p>I've omitted the other three options in the questions because I could understand why they were wrong. I was just confused between two options.</p>
<hr>
<p>If 0 ≤ x ≤ y and (x + y)^ 2 − (x − y)^ 2 ≥ 25, what is the least possible value of y ? </p>
<p>Answer given is 2.5. How?</p>
<p>In response to the writing question, you want to keep the sentence parallel. </p>
<p>Explaining modern art is impossible, partly because of its complexity (noun) but largely because {of it rapidly changing}<—also needs to be a noun.</p>
<p>Rapidity is a noun and therefore is the correct choice.</p>
<p>And I don’t know about the math question…I didn’t look at it, sorry. =p</p>
<p>^Lol ok. Thanks for the writing thing though. - I totally forgot about parallelism.</p>
<p>On simplifying the eqn, we get
xy = 6.25</p>
<p>Now, 0 ≤ x ≤ y .
The smallest possible value of y is when it is equal to x.</p>
<p>y^2= 6.25
y=2.5</p>
<p>^I’m a blot on the capabilities of Indians, especially since I had gotten to the last step and then stopped there. 
</p>
<p>Thanks anyway pixie.</p>
<p>No worries, hota hai!</p>