the terms of AP.
19. Sum of first six terms of an AP is 42. The ratio between its 10th term and 30th term
is 1: 3. Find

the terms of AP.
19. Sum of first six terms of an AP is 42. The ratio between its 10th term and 30th term
is 1: 3. Find its first term and 13th term of the AP.
20. The angles of a polygon are in A.P with common difference 50. If the smallest angle
is 120°, find the number of sides of the polygon
21. An arithmetic progression consists of 37 terms. The sum of first three terms is 12
and the sum of last three terms is 318. Find the first term and the last term of AP.
22. The sum of first 7 terms of an AP is 140. The sum of next seven terms is 385. Find
he first four terms of the AP.
23. The sum of first five terms of AP is one fourth of sum of next five terms. If first term
s 2 find S20
first​