(2)1÷10% =10 (ten thousand sheets); ( 1× 200+2× 120+6× 100+ 1× 90) ÷ ( 1+2+6+ 1) = 1658.
By 20: 00 on June 5438+05, 65438+ ten thousand tickets had been sold at the scene, with an average fare of 1 13 yuan; ((2 points)
(3) List: (3 points) A, D? ? b,D? Washington, D.C. ? Oh, god. a,D? b,D? b,D? c,D -? D D? a,C? b,C? b,C -? Washington, DC? Washington, DC? A, B, C and D. B,B -? c,B? d,B? d,B? a,B -? B,B? c,B? d,B? d,B-? b,A? b,A? c,A? d,A? There are 30 cases of D, A∴ a * *;
The possibility of each situation is the same.
∴P (two brothers get tickets for the evening performance at the same time) = 230 = 1 15 (2 points)