Let the total number of students appeared for IBPS PO preliminary exam from be S
Total number of students who appeared for IBPS PO preliminary exam from Maharashtra, Karnataka and Tamil Nadu together = (20% +18% +14%) x S = (52% x S).
Average number of students who appeared for IBPS PO preliminary exam from Maharashtra, Karnataka and Tamil Nadu together = (52% x S)/3
Total number of students who appeared for IBPS PO preliminary exam from Uttar Pradesh and Kerala together = (30% +8%) x S = (38% x S).
Required ratio = ((52% x S)/ 3 x (38% x S)) = 26/57.