Rule 10B of the Income-tax Rules, 1962, provides the methods for determining the arm's length price in international transactions between associated enterprises. This rule is crucial for ensuring that transactions between related parties are conducted as if they were between unrelated parties, thereby preventing tax evasion through transfer pricing. The rule outlines five methods: Comparable Uncontrolled Price (CUP) Method, Resale Price Method, Cost Plus Method, Profit Split Method, and Transactional Net Margin Method. Each method has specific criteria and applicability, and the choice of method depends on the nature of the transaction and availability of data. The burden of proof lies with the taxpayer to justify the method used and the arm's length price determined. This rule is significant as it helps maintain fairness and transparency in cross-border transactions, ensuring that profits are taxed where they are generated.