Find the sum of the first 22 terms of the AP : 8, 3, –2, . . .

If the sum of the first 14 terms of an AP is 1050 and its first term is 10,find the 20th term.

How many terms of the AP : 24, 21, 18, . . . must be taken so that their sum is 78?

Find the sum of the first 1000 positive integers

-979

200

4 or 13

500500