Arithmetic Prog...

Find  which the term of the A.P. 20, 30, 40.... is 100.

Find the sum of the following AP : $$2 , 4 ,6 , 8 ,...... (15  $$  terms).

Which term of the A.P. 18, 16, 14.... is -20?

Find the sum of the first 20 terms if the first term is -12 and the common difference is -5 in an arithmetic series.

In an arithmetic series, find the sum of the first 10 terms if the first term is 3 and the common difference is 4.

What is the sum of the first $$n$$ terms if the first term is $$2$$, the common difference is $$5$$ and the $$n^{th}$$ term is $$122$$ in an arithmetic series?

In an arithmetic series, $$a_1 = -14$$ and $$a_{5}=50$$. Find the sum of the first 5 terms.

If the first term of an arithmetic sequence is $$-14$$ and the common difference is $$2$$, find the sum of the first $$8$$ terms.

$$a_1=1.5, a_{20}=58.5$$ in an arithmetic series, find $$S_{15}$$.

Given A.P is $$\dfrac{1}{3q},\dfrac{1-6q}{3q}, \dfrac{1-12q}{3q}$$. Find the common difference