Mathematics
The sum of first 15 terms of an A.P. is 750 and its first term is 15. Find its 20th term.
Related Questions
The first and the last terms of an A.P. are 17 and 350 respectively. If the common difference is 9, how many terms are there and what is their sum?
Solve for x : 1 + 4 + 7 + 10 + … + x = 287.
In an A.P. (with usual notations):
(i) given a = 5, d = 3, an = 50, find n and Sn
(ii) given a = 7, a13 = 35, find d and S13
(iii) given d = 5, S9 = 75, find a and a9
(iv) given a = 8, an = 62, Sn = 210, find n and d
(v) given a = 3, n = 8, S = 192, find d.
The first term of an A.P. is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.