Bunuel wrote:

P and Q are each circular regions. What is the radius of Q, if the area of P minus the area of Q is 15π and P has a circumference that is 4 times that of Q?

Let the radius of Circular region P be p and that of Q be q

Given:

\(2\pi*p=4*2\pi*q\)

this implies, \(p=4q\).................a

Also, \(\pi*p^2-\pi*q^2=15\pi\)

therefore, \(p^2-q^2=15\)

Using a, we get

\(16q^2-q^2=15\)

\(15q^2=15\)

therefore, \(q^2=1\)or \(q=1\)

Answer: B
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~R.

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