Arithmetic Prog...

If the sum of all the terms of an A.P.: $$25, 22, 19, ......,$$ $$t_n$$ is $$116,$$ then $$n$$ is

In an A.P., if the common difference is $$2$$ and sum up to $$n$$ terms is $$49$$ and $$7^{th}$$ term is $$13$$, then value of $$n$$ is equal to?

In an A.P., if $$a = 3.5$$, $$d = 0$$, $$n = 101$$, then $$a_n$$ will be

 For  an  A.P.  $$a_1,a_2,...a_n$$   and $$a_1=\frac{5}{2},a_{10}=16$$.
 If  sum of $$n$$  terms is $$110$$  then $$n$$  equals

If $$8^{th}$$ term of an A.P is $$15$$, then the sum of $$15$$ terms is

The $$11^{th}$$ term of the series $$ \displaystyle -5,\frac{-5}{2},0,\frac{5}{2},\cdots$$ is

If the first term of an AP is $$5$$ and the common difference is $$-2,$$ then the sum of the first $$6$$ terms is

In an AP if $$a = 1$$, $${ a }_{ n }=20$$ and $${ S }_{ n }=399$$, then $$n$$ is

If the common difference of an AP is $$5,$$ then what is $$a_{18}-a_{13}$$ ?

Which term of the AP, $$21, 42, 63, 84,...$$ is $$210?$$