Question

The value of (7c0+7c1) + ( 7c1+ 7c2) + .....(7c6+ 7c7) is

Answer 1

Hey

$\sum _{k = 0}^{n} \binom{n}{k} = {2}^{n}$

Now, back to original question :

$\sum _{k = 0}^{6} ( \binom{7}{ k} + \binom{7}{k + 1} )= 2\sum _{k = 0}^{6} \binom{7}{k}$

$= 2( {2}^{7} - 1)$

$= 127 \times 2 = 254$

Answer 2

Answer:

2^8-2

Step-by-step explanation:

using permutation and combination forumla 2n-1

we get 2^8-1-1