A stadium charges $75 for each seat in section A, $50 for each seat in section B, and $40 for section C. There are three times as many seats in section B as in section A. The revenue from selling odd 20,000 seats is 897,500. Write a system to represent the situation. A. b=3×c
a+b+c=20,000
75a+50b+40c=897,500

B. b=3×a
a+b+c=20,000
75a+50b+40c=897,500

C. a=3×b
a+b+c=20,000
40a+50b+75c=897,500

D. a=3×b
a+b+c=20,000
75a+50b+40c=897,500

For every corresponding pair of cross sections, the area of the cross section of a sphere with radius r is equal to the area of the cross section of a cylinder with radius and height 2r minus the volume of two cones, each with a radius and height of r. a cross section of the sphere is and a cross section of the cylinder minus the cones, taken parallel to the base of cylinder, is the volume of the cylinder with radius r and height 2r is and the volume of each cone with radius r and height r is 1/3 pie r^3. so the volume of the cylinder minus the two cones is therefore, the volume of the cylinder is 4/3pie r^3 by cavalieri's principle. (fill in options are: r/2- r- 2r- an annulus- a circle -1/3pier^3- 2/3pier^3- 4/3pier^3- 5/3pier^3- 2pier^3- 4pier^3)