Answer:
E = V / d 125 V / .018 m = 6940 V/m electric field
F = E Q force on Q due to E
F = E n e where n is the number of electrons in Q
m g = E n e
n = m g / E e where n is the number of electrons e needed to support drop
n = 1.6 * 10E-16 * 9.8 / (6940 * 1.6 * 10E-19)
n = 1.41
Since n needs to be an integral number of charges, the drop would
not be suspended (motionless under these conditions).
