Question

20*cr= 20*cr-10, then 18cr is equal to​

Answer 1

Answer:

456579545785_580:'$468076690

Answer 2

$\displaystyle\huge\red{\underline{\underline{Solution}}}$

FORMULA TO BE IMPLEMENTED

$\displaystyle \: ^nC_r = \: ^nC_p \: \: implies \: </u></em></strong><strong><em><u>either</u></em></strong><strong><em><u> \: r \: = p \: \: \: \: or \: \: r + p = n$

CALCULATION

$\displaystyle \: ^{20}C_r = \: ^{20}C_{r - 10}$

Since

$r \ne r - 10$

So by the above formula

$r + r - 10= 20$

$\implies \: 2r \: = 30$

$\therefore \: r = 15$