clearly d = -k/3
S30 = 30/2 (2k + 29(-k/2)) = -375k/2
An AP is given k,2k/3,k/3,0....calculate the sum of the first 30 terms
2 answers
small typo in Steve's answer:
last line should be
S30 = 30/2 (2k + 29(-k/3))
= 15(-23k/3)
= -115k
last line should be
S30 = 30/2 (2k + 29(-k/3))
= 15(-23k/3)
= -115k