Department of Mathematics and Statistics at Washington ...

(b)divisible by 3 or less than or equal to 27? (c) neither divisible by 3 nor less than or equal to 27 (greater than 27)? S = f1;2;:::;999g; n(S) = 999; A = \numbers that are divisible by 3" ˆS; B = \numbers that are less than or equal to 27" ˆS; (a) A\B = \numbers that are divisible by 3 and less than or equal to 27" n(A\B) = 27 3 ................
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