1. The problem statement, all variables and given/known data The electric field, E, a distance D away from a charged particle is directly proportional to the size of the charge Q, and inversely proportional to the square of the distance D. If the charge is increased by 40% and the distance is increased by 30%, by what percentage does the electric field change? 2. Relevant equations ??? 3. The attempt at a solution I'm actually pretty upset with how rusty I am at this but for some reason when I read these problems (and precalculus gravitational problems), I can't seem to get Classical Mechanics and Electromagnetism equations out of my mind. Although, I know that the answer will pretty much apply Coulomb's Law. Maybe I'm overthinking this.. ED = Q = 1/D^2 +.35(Q) +.2(D) Is all I'm interpreting from the question.