Question

Find the sum of the series 1 + (1 + 2) + (1 + 2 + 3) + (1 + 2 + 3 + 4) + ... + (1, +2 +3 + ... + 20).
(A) 1470
(B) 1540
(C) 1610
(D) 1370​

Answer 1

Answer:

please give some time......