Q.30 A metallic sphere of radius 10 cm is melted and recast into 2 small spheres of equal radii. The radius of the small spheres is 7.93700526 cm. What is the percentage change in total surface area?
A. -50% B. -37.0% C. 26.1% D. 41.4%
Answer is C.求過程
Q.31 A spherical orange has diameter 6 cm. If its peel is 5 mm thick, what is the volume of the peel?
A. 26.8 cm³ B. 44.8 cm³ C. 47.6 cm³ D. 79.6 cm³
Answer is C.求過程
Q.36 A boiling tube is composed of a cylindrical part and a hemispherical part. The surface area of the boiling tube is 24兀 cm². When 8兀 cm³ of solution is poured into the tube, what is the depth of solution in the tube?
圖片參考:http://imgcld.yimg.com/8/n/HA01113436/o/20130105234133.jpg
A. 20/3 cm B. 22/3 cm C. 23/3 cm D. 25/3 cm
Answer is B.求過程