Question

15C10+15C11=? jldii btaa day koii..

Answer 1

Here is ur answer..

Hope it helps

Answer 2

Answer:

$\red {Value \:of \: ^{15}C_{10} + ^{15}C_{11} }$

$\green {= 4368}$

Step-by-step explanation:

$Value \:of \: ^{15}C_{10} + ^{15}C_{11} \\= \frac{15!}{(15-10)! 10!} + \frac{15!}{(15-11)! 11!}$

$\boxed {\pink { ^{n}C_{r} = \frac{n!}{(n-r)! r! }}}$

$= \frac{15!}{(5)! 10!} + \frac{15!}{4! 11!}$

$= \frac{ 15\cdot14\cdot13\cdot12\cdot11\cdot10!}{5\cdot4\cdot3\cdot2\cdot1\times 10!} + \frac{ 15\cdot14\cdot13\cdot12\cdot11!}{4\cdot3\cdot2\cdot1\times 11!}$

$= 7\times 13 \times 3 \times 11 + 15\times 7 \times 13\\= 3003 + 1365\\= 4368$

Therefore.,

$\red {Value \:of \: ^{15}C_{10} + ^{15}C_{11} }$

$\green {= 4368}$

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