Given: 40% of a number is less than its 60% by 30. Formula: x% of a number = Actual number × (x/100) Calculation: Let a number be x, then According to the question x×(60/100)−x×(40/100)=3 0 ⇒x×(20/100)=30 ⇒x=30×5 ⇒ x = 150 Hence, 20% of 150 ⇒150×(20/100) ⇒ 30