Question

What is the sum of all integers between $50$ and $350$ which end in $1$?

• A. $5880$
• B. $5539$
• C. $5208$
• D. $4566$

Answer 1

The correct option is A $5880$

$a=51$

$d=10$

$n^{th}$ term $=341$

$\therefore 51+(n-1)10=341$

$\Rightarrow n=30$

$\therefore Sum=\frac{30}{2}[2.51+(30-1\left)10\right]=5880$

$(Ans\to A)$