## virtus 2 years ago 16Cn +16C9 =17C9

1. lgbasallote

$16Cn \implies \frac{16!}{n!(16-n)!}$ $16C9 \implies \frac{16!}{9!(16-9)!}$ $17C9 \implies \frac{17!}{9!(17-9)!}$ does that help?

2. virtus

so how do you find n?

3. hartnn

u know that property: $^nC_r+^nC_{r-1}=^{n+1}C_r$ ?

4. hartnn

@virtus use this property, and put n=16,r=9 so now can u find your 'n' ??

5. satellite73

oh i see, your job is to find $$n$$ for thie equality correct?