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Total possible committees  = 30C3  = 4060

Committees with 0 juniors  =  19C3  = 969

Committes with 1 junior  = 11C1 * 19C2  = 1881

Committees with 2 juniors  = 11C2 * 19C1  = 1045

Committees with 3 juniors  = 11C3  = 165

So...the expected value is

0(969/4060) + 1(1881/4060) + 2(1045/4060) + 3(165/4060) =  1.1