Net force on 1/3 due to the other two is found as follows.
11 is pushed to the left by 1/3 and pulled to the right. by 12
Taking right as positive
F = kq1 (q3 (d1 + d2) ^2 - q2 /d1^2}
F = 9e9* 6.24e-6* 1 e-6 {(2.06/ (0.05) ^2 – (1.39 /0.03^2)}
F = - 40. 46 N
