1. The problem statement, all variables and given/known data The electric potential at a position located a distance of 18.6 mm from a positive point charge of 7.50×10-9C and 10.9 mm from a second point charge is 1.02 kV. Calculate the value of the second charge. 2. Relevant equations q2 = r2 * (v - (k * q1 / r1)) / k 3. The attempt at a solution v = 1.02 kV = 1.02 x 10^3 V = 1020 V q1 = 7.50 x 10^-9 C r1 = 18.6 mm = 0.0186 m r2 = 10.9 mm = 0.0109 m k = 9 x 10^9 Nm^2/C^2 q2 = (.0109) * (1020 - (9E9*7.5E-9/.0186)) / 9E9 q2 = -3.15E-9 nC I keep getting the same answer but the homework system says it's wrong!