If the angles of a quadrilateral are in $A.P.$ whose common difference is ${10^o}$, then the angles of the quadrilateral are
${65^o},\,{85^o},\,{95^o},\,{105^o}$
${75^o},\,{85^o},\,{95^o},\,{105^o}$
${65^o},\,{75^o},\,{85^o},\,{95^o}$
${65^o},\,{95^o},\,{105^o},\,{115^o}$
Let $S_{n}$ be the sum of the first $n$ terms of an arithmetic progression. If $S_{3 n}=3 S_{2 n}$, then the value of $\frac{S_{4 n}}{S_{2 n}}$ is:
Show that the sum of $(m+n)^{ th }$ and $(m-n)^{ th }$ terms of an $A.P.$ is equal to twice the $m^{\text {th }}$ term.
The sums of $n$ terms of two arithmetic progressions are in the ratio $5 n+4: 9 n+6 .$ Find the ratio of their $18^{\text {th }}$ terms.
If $a,\;b,\;c,\;d,\;e,\;f$ are in $A.P.$, then the value of $e - c$ will be
The sum of integers from $1$ to $100$ that are divisible by $2$ or $5$ is