The sum of 40 terms of the A.P. 7 + 10 + 13 + 16 + ….. is :

1. 5240

2. 2620

3. 1310

4. 2680

The n^th term of an A.P. is 6n + 4. The sum of its first two terms is :

1. 16

2. 20

3. 26

4. none of these

Find the sum of 28 terms of an A.P. whose n^th term is 8n - 5.

Find the sum of all odd natural numbers less than 50.