What is the sum of the 10^th, 20^th, 30^th and 40^th terms of the sequence: S_n = S_{n - 1} - 10, if it is given that S₃ = 0?

Given the recursive formula Sn = Sn - 1 - 10 and S3 = 0, this sequence is an arithmetic progression with a common difference of -10. Using the nth term formula, the 10th term is 0 + (10 - 3)(-10) = -70, the 20th term is 0 + (20 - 3)(-10) = -170, the 30th term is 0 + (30 - 3)(-10) = -270, and the 40th term is 0 + (40 - 3)(-10) = -370. Adding these four terms gives (-70) + (-170) + (-270) + (-370) = -880.

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