This is from an entrance test to a private junior high school (11-year-olds) in Japan:1. Name the two regions in the United States where export-oriented rice is grown. A) Colorado River Delta B) Missouri River C) Prairies D) Columbia Basin E) Sacramento River F) Mississippi River Delta Here's one from a Japanese university entrance exam: 2. What is the maximum volume of a tetrahedron whose proportions of the distances between the four points is as follows: OA = 1; OB = OC = OD = 4. Answers: 1. E, F 2. V(2) = 9 x square root of 3.