Volume vs Area of Sphere

[hijazim]

This question has a wording problem. If I am not wrong the volume should be 4/3*pi*r^3 and not 4/3*pi*r^-3.

Any help please. The OA is D. But I couldn't interpret how???

[DanaJ]

You are right, that (-3) does not belong there. It may be a typo, it's surely not correct. Check Wikipedia when in doubt!
Now, back to the question: it says here that the volume of the sphere is 972Pi, which will be (4/3)*Pi*(r^3):
972 = 1000 - 28 = 4*250 - 4*7 = 4*243
So you have that (4/3)*(r^3) = 4*243
This makes r^3 = 243*3 = 729 or 9^3, making r = 9.

This means that the total surface area will be 4Pi(r^2) = 4*81*Pi = 324Pi.
Since my answer is consistent with the OA, it was indeed just a typo.

[hijazim]

Yes man, this is it. Thanks for sharing