Explanation
We have two circles, and we need to find the radius of the
smaller one. The circumference, area, or radius of either the larger or smaller
circle will be sufficient to do so. On to the statements, separately first.
Statement (1) tells us that the radius of the garden is 5.
The radius of the well is
that of the
garden, so the radius of the well is 1, and the area of the mouth of the well is
. We have answered the question definitively, so
Statement (1) is sufficient.
Statement (2) gives us the circumference of the larger
circle. From it, we know that the circumference of the smaller circle is
. Therefore, the radius of the smaller circle is 1
and the area is
. We have answered the question definitively, so
Statement (2) is sufficient. The correct answer is (D). Since various facts
about a circle gives us its radius and the radius gives us all of those things
in turn, Data Sufficiency questions involving circles tend toward sufficiency.
Again, the correct answer is (D).
If you believe you have found an error in this question or explanation, please contact us and include the question title or URL in your message.