A certain rectangular crate measures 12 feet by 16 feet by 18 feet. A cylindrical gas tank is to be made for shipment in the crate and will stand upright when the crate is placed on one of its six faces. What should the radius of the tank be if it is to be of the largest possible volume?	Choose the correct choice.
A) 4  B) 5  C) 6  D) 8  E) 10

Rationale: for max volume of cylinder ( pi * r ^ 2 * h ) we need to max out r ^ 2 * h . we do n ' t know what the dimensions of the crate refer to . . therefore for max vol base should be 18 x 16 i . e . of radius 16 / 2 = 8 d
Answer: D