physics test

at last.. the physics test is over.. even though there is a lot more of exam ahead.. I'm doing pretty well in this exam..based on my feeling only, the result will probably out next week if Mr Jawad struggles to mark the test paper during the weekend... the only doubt and curious in my mind is about of the questions...if i'm not mistaken the calculation part to find the distance between the two charges... I don't know whether the answer is right or not..