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Ten Married couples.

Author:
ortollj

Ten Married couples.

Ten Married couples. Let Xj indicate if the jth man sits across from his wife. Then E(Xj) = 1/19, since no matter where the man sits, his wife can sit in 19 other possible chairs, only 1 of which is directly across from him. Thus the expected number of men sitting across from their wives is : E(X1 + .... + X10) = E(X1) + ... + E(X10) = 1/19 + ..... + 1/19 = 10/19=0,53."