Answer should be
C.
Question: Two missiles are launched simultaneously. Missile 1 launches at a speed of \(x\) miles per hour, increasing its
speed by a factor of \(\sqrt{x}\) every \(10\) minutes (so that after \(10\) minutes its speed is \(x\sqrt{x}\), after \(20\) minutes its speed is \(x^2\), and so forth). Missile 2 launches at a speed of \(y\) miles per hour, doubling its speed every \(10\)
minutes. After \(1\) hour, is the speed of Missile 1 greater than that of Missile 2?
So we know that after \(60\) minutes:
Speed of \(x\) will be \(= x^4\)
Speed of \(y\) will be \(= 64y\)
The question is asking, is \(x^4>64y\) ?
Statement 1: \(x=\sqrt{y}\)
Lets subtitute in \(x^4>64y\):
So the question is asking, is \(y^2>64y\)
Since we know all values are positive, reduce to, is \(y>64\). We have no way to establish this.
Hence Insufficient.
Statement 2: \(x > 8\) . No info about \(y\).
Hence Insufficient.
Combined A&B:
we know that \(x>8\) and we want to find out that \(y>64\) or not.
But \(x=\sqrt{y}\)
So \(\sqrt{y}>8\), so \(y>64\).
Hence Sufficient. Answer
C.
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"Nowadays, people know the price of everything, and the value of nothing." Oscar Wilde