Given: A bag contains coins of 1 rupees, 50 paise and 25 paise in the ratio of 1 : 2 : 4. Calculation: Let the number of coins of 1 rupees, 50 paise and 25 paise be x, 2x and 4x. Total money = 225 ⇒ x + 2x/2 + 4x/4 = 225 ⇒3x = 225 ⇒x = 75 ⇒Number of coins of 50 paise = 2x = 150 ∴ Number of coins of 50 paise is 150.