Given that the reaction for fresh feed A and B is
2A + 5B ------> 3C + 6D
in a reactor with recycle, find the desired recycle ratio (moles recycled/moles fresh feed) if in the fresh feed A is 20% in excess, the once through conversion of B is 60%, and the overall conversion of B to products from the overall process is 90%. After the products exit from the reactor, a stream of pure B is separated from the products and forms the recycle. Assume 1 mol of B in the feed as a basis.