The two successive terms in the expansion of  (1 + x)24 whose coefficients are in the ratio 1:4 are

Given expression is (1+x)24  Let two successive terms are (r + 1)th and (r + 2)thterms ⇒ Tr+1=24Crxr and Tr+2=24Cr+1xr+1Now, ratio of coefficients = 1 ⇒  24Cr 24Cr+1=14⇒r+124−r=14⇒ 4r+4=24−r⇒r=4.'. Required terms are 5th and 6th.