If 16Cr= 16Cr+2, then find rC4.
16Cr=16Cr+2
Use the formula: nCx=nCy⇒x+y=n
r+r+2=16
2r+2=16
r=7
rC4=7C4=7!4!3!=7⋅6⋅53⋅2⋅1=35
Thus, the value is 35.
If 16C2r=16Cr+2′ find rC4