Question

Subba rao started work in $1995$ at an annual salary of $Rs5000$ and received an increment of $Rs200$ each year. In which year dis his income reach $Rs7000$?

Answer 1

Salary in 1995 (1^st year) $=5000$

In 2^nd year$=5000+200=5200$

In 3^rd year $=5400$

Series is $5000,5200,5400,....$

$d=200,a=5000,an=7000$

Now $an=a+\left(n-1\right)d$

$7000=5000+\left(n-1\right)200$

$\Rightarrow 2000=\left(n-1\right)200$

$\Rightarrow \frac{2000}{200}=n-1$

$\Rightarrow 10=n-1$

$\Rightarrow n=11$

In 11^th year subbarao’s salary became $7000$