Question

If the numerically greatest term in the expansion of $(1-3x{)}^8$ for $x=\frac{1}{2}$ is $T_r$ then ' $r$ ' is

• A. 2
• B. 4
• C. 6
• D. 8

Answer 1

Answer: (C)

$\frac{T_{r+1}}{T_r}=\frac{3}{2}\gtrless 1$
$27\gtrless 5r$
$\text{ for }r=5T_6>T_5$
$\text{ for }r=6T_7<T_6$
$\therefore T_6\text{ is numerically greater }$