Question

$n ^ { t h }$ term of the series $3.8 + 6.11 +$ $9.14 + 12.17 + \ldots$. will be

• A. $3 n ( 3 n + 5 )$
• B. $3 n ( n + 5 )$
• C. $n ( 3 n + 5 )$
• D. $n ( n + 5 )$

Answer 1

Answer: (A)

$3 n ( 3 n + 5 )$

Answer 2

Given series

First factors are 3, 6, 9, 12 whose $n ^ { t h }$term is $3 n$ and second factors are 8, 11, 14, 17

$t _ { n } = [ 8 + ( n - 1 ) 3 ] = ( 3 n + 5 )$

Hence $n ^ { t h }$term of given series $= 3 n ( 3 n + 5 )$.