Given that {an} is an arithmetic sequence, a1 + A2 +. + A50 = 200, A51 + a52 +. + A100 = 2700, then what is A1 equal to

Given that {an} is an arithmetic sequence, a1 + A2 +. + A50 = 200, A51 + a52 +. + A100 = 2700, then what is A1 equal to

Because {an} is an arithmetic sequence, and a1 + A2 +. + A50 = 200, A51 + a52 +. + A100 = 2700, so (A51 + a52 +. + A100) - (a1 + A2 +. + A50) = (a51-a1) + (a52-a2) +... + (a100-a50) = 50D + 50D +... + 50D = 2500d = 2700-200 = 2500, so d = 1 and S50 = 50 * (a1 + A50) / 2 = 200, so a1 + A50 = 8