Question

please tell the answer now​

Answer 1

❏Question:-

$\sf \: in \: an \: arithmatic \: progression \: t_1 \: = 10 \\ \sf \: t_n = 100 \: \: and \: n = 10 \: then \:find \: s_n .$

❏Answer :-

→ Option C is correct .

$\implies \sf s_n = 550$

❏Used Formula :-

$\implies \sf \: s_n = \frac{n}{2} \{t_1 + t_n \}$

❏ Solution :-

Given that ,

$\to \sf t_1 = 10, \: t_n = 100 \: and \: \: n = 10 \\ \\ \sf substitute \: these \: values \: in \: the \: \\ \sf given \: formula \\ \\ \to \sf \: s_n = \frac{10}{2} \{10 + 100 \} \\ \\ \to \sf s_n = 5\times 110 \\ \\ \to \boxed{\sf s_n = 550}$

Sum of n terms is 550 .