Given the sequence defined by $a_n = 48 - 3n$, find all possible values of $k$ so that \[a_1 + a_2 + a_3 + \cdots + a_k = 330.\]
Using the formula for an arithmetic series, k works out to 13.
a=listfor(n, 1, 11, (48 - 3*n))=(45, 42, 39, 36, 33, 30, 27, 24, 21, 18, 15)==11 terms==330
oh yeah forgot this was here i solved it already its 11 and 20 btw
