Q.

If (1C015+1C115)(1C115+1C215)⋯(1C1215+1C1315)=α13C014 14C1⋯ 14C12, then 30α is equal to_____ [2026]


Ans.

(32)

∏r=012(1Cr15+1Cr+115)=∏r=01216r+1·Cr1515Cr·Cr+115

=∏r=01216(r+1)·15r+1·Cr14=∏r=0121615Cr14

=(1615)13C014·C114⋯C1214⇒α=1615

⇒30α=32