WA = 2WB
P = WA+WB = 3WB
Q = √3 (WA-WB) = √3 WB
S = √(P2+Q2) = √(9WB2 + 3WB2) = 2√3 WB
P.F. = P / S = 3WB / (2√3 WB) = 0.866