How do you evaluate 5C2 + 5C1?

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Answer 1 · 2016-02-04T14:25:28

$5 C 2 + 5 C 1 = 15$ $5C2+5C1=15$

$5 C 2 + 5 C 1 = \frac{5!}{(5 - 2)! 2!} + \frac{5!}{(5 - 1)! 1!}$ $5C2+5C1=(5!)/((5-2)!2!)+(5!)/((5-1)!1!)$

$= \frac{5 \cdot 4 \cdot 3!}{3! 2!} + \frac{5 \cdot 4!}{4! 1!}$ $=(5*4*3!)/(3!2!)+(5*4!)/(4!1!)$

$=(5*4*cancel3!)/(cancel3!2!)+(5*cancel4!)/(cancel4!1!)$

$=(5*4)/(2!)+(5)/(1!)$

$=(5*4)/2+(5)/1$

$=10+5$

$15$

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