Question

{1,2,3,4,5,6, 7} kümesinin 3 elemanlı bencil altkümelerinin sayısı kaçtır?

Answer 1

Given:

set= $\{ 1,2,3,4,5,6,7\}$

To find:

3-element selfish subsets= ?

Solution:

Formula:

$\bold{C(n,r) = \frac{n!}{r! (n-r)!}}$

$C(7,3) = \frac{7!}{3!(7-3)!}= \frac{7!}{3! \times 4!}$

                           $= \frac{7 \times 6 \times 5 \times 4! }{3\times 2 \times 1 \times 4!} \\\\= \frac{7 \times 6 \times 5 }{3\times 2 \times 1} \\\\= \frac{7 \times 6 \times 5 }{6} \\\\= 7 \times 5\\\\=35$

There are 35 ways to find 3-element selfish subsets.

Answer 2

selam türkçe konuşan kardaşım

C(n,r)=

r!(n−r)!

n!

C(7,3)=

3!(7−3)!

7!

=

3!×4!

7!

=

3×2×1×4!

7×6×5×4!

=

3×2×1

7×6×5

=

6

7×6×5

=7×5

=35