I need help with these two questions. Can someone explain these two step-by-step so that I can get a better understanding. Thank you.

1. We have two identical metal spheres A and B. Sphere A is electrically neutral, and sphere B has an initial charge of -13 nC. Suppose we add +20 nC of charge to sphere A. Next the sphere's are brought together so that they make contact and then they are separated. N=neutral B -13nc (a) How many electrons were transferred between the spheres? (b) Which sphere gained electrons during the transfer? + 20nc added 2. Three charges are arranged in a vertical line as shown in the figure, with q 0. Initially, the 4q charge is placed a distance 4L above the middle charge (not shown). We want the net force on the middle charge to flip its direction by 180 (and keep the same magnitude), by moving the 4q charge to a new distance L'. Determine L' in terms of any of the given variables and any necessary fundamental constants. Ignore any gravitational forces. 4o