If first term $a$, last term $p$ and number of terms $n$ are known, the sum of an arithmetic series is —

Question

Accepted Answer

$\dfrac{n}{2}(a + p)$

Answer

$\dfrac{n}{2}(a - p)$

Answer

$n(a + p)$

Answer

$\dfrac{1}{2}(a + p)$

If first term aaa, last term ppp and number of terms nnn are known, the sum of an arithmetic series is —