Hi! Some progressive B-Schools do look at Art graduates. Usually the key issue with preperation is Math as you said and it has to be worked on. Math requires "regular practice". Initially all the areas might seem vauge. So slowly start with areas which are considered basic like numbers, HCF, LCM, Percentages because unless you are strong on all these, you will face problems in other areas like profit and loss etc. So you need to move step by step. It all starts from the understanding how improtant