A) 183
B) 186
C) 197
D) 185
Correct Answer: D
Solution :
Required number \[={{\,}^{20}}{{C}_{2}}\,-{{\,}^{4}}{{C}_{2}}\,+\,1\] \[=\frac{20\times 19}{2}-\frac{4\times 3}{2}+1=190-6+1=185.\]You need to login to perform this action.
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