Nth term of A.P

Q. If the 9^th term of an A.P. be zero, then the ratio of its 29^th and 19^th term is

1. 1 : 2

2. 2 : 1

3. 3 : 1
4. 1 : 3

Q.

If the 7th term of a H.P is $\frac{1}{10}$ and the 12th term is $\frac{1}{25}$, then the 20th term is

1. 

2. 

3. 

4. 

Q. If n^th terms of two A.P.'s are 3n + 8 and 7n + 15, then the ratio of their 12^th terms will be
[MP PET 1986]

1. 4/9

2. 7/16

3. 3/7
4. 8/15

Q. In the sum fo first n terms of an A.P. is $c{n}^2$ then the sum of squares of these n terms is

1. $\frac{n(4n^2-1)c^2}{6}$
2. $\frac{n(4n^2+1)c^2}{3}$
3. $\frac{n(4n^2-1)c^2}{3}$
4. $\frac{n(4n^2+1)c^2}{6}$

Q. 8^th term of the series $2\sqrt{2}+\sqrt{2}+0+....$ will be

1. $-10\sqrt{2}$
2. $-5\sqrt{2}$
3. $5\sqrt{2}$
4. $10\sqrt{2}$