Patrick has assignments in 5 subjects he can only do two assignments in how many ways can he do two assignments
We use the formula of combinations "C_k^n=\\frac{n!}{k!(n-k)!}", "n>k".
We have "5" subjects, so "n=5".
Patrick can only do two assigments, so "k=2".
Number of ways can do two assignments equals "C_2^5=\\frac{5!}{2!(5-2)!}=\\frac{5!}{2!3!}=\\frac{5\\cdot4\\cdot3\\cdot2\\cdot1}{2\\cdot1\\cdot3\\cdot2\\cdot1}=5\\cdot2=10".
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