Question

For an A.P. if $t_4=12$ and $d=-10$, then its general term is

• A. −10n+57
• B. −10n+52
• C. −10n+53
• D. −10n+51

Answer 1

Answer: (B)

−10n+52

Let $a$ be the first term and $d$ be the common difference of given AP.
Hence given that $t_4=12$ and $d=-10$.
$\Rightarrow a+3d=12$
$\Rightarrow a+3\times -10=12$
$\Rightarrow a=12+30=42$
general term of an AP is: $t_n=a+(n-1)d$
$\Rightarrow t_n=42+(n-1)\times -10$
$\Rightarrow t_n=-10n+52$