1. The problem statement, all variables and given/known data The potential equals 7.52 V at the midpoint between two point charges that are 0.91 m apart. One of the charges is 1.11 x 10-9 C. Find the value of the other charge. 2. Relevant equations V = k [sum] (q/r) 3. The attempt at a solution 7.52=k[(1.11 x 10-9 / 0.455m ) + ( x / 0.455m )] This gives me -7.3x10^-10, which is incorrect, but I cannot think of any other way to approach this problem.