My submission 97108301 of problem 1437A - Marketing Scheme got wrong answer on test case 7 using float during contest but using double it is getting accepted after the contest. After searching a lot on internet , I am not getting a satisfactory answer. Can someone give me a proper reason why it is giving wrong answer using float?

Since I am doing regular practice of A and B level questions but in real contest ,I am not able to see improvement in my performance like solving questions fast and my rating gets decreased and now I am confused how to do better .Please help me Thanks in advance