Tr+1=15Cr(x2)15−r⋅(2x−1)r=15Cr×(2)r×x30−3r For independent term, 30−3r=0⇒r=10 Hence the term independent of x, T11=15C10×(2)10 For term involve x15,30−3r=15⇒r=5 Hence coefficient of x15=15C5×(2)5 Required ratio =15C10×(2)1015C5×(2)5=5!10!15!×(2)510!5!15!=1:32