Let U={1,2,…,20}U = \{1, 2, \dots, 20\}U={1,2,…,20}. Let A={x∈U:x is prime}A = \{x \in U : x \text{ is prime}\}A={x∈U:x is prime} and B={x∈U:x is even}B = \{x \in U : x \text{ is even}\}B={x∈U:x is even}. Find n(A∖B)n(A \setminus B)n(A∖B).
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