Question

if 15C3+2×15C4+15C5=17C5​

Answer 1

Answer:

=17C5

Step-by-step explanation:

We know, nCr + nCr-1 = n+1Cr

Therefore,

 = 15C3 + 15C4 + 15C4 + 15C5

Arranging the terms,

 = 15C4 + 15C3 + 15C5 + 15C4

Applying the property,

 = 16C4 + 16C5

 = 17C5

Hence proved!