Successive discounts of 10%, 20% and 30% is equivalent to single discount of?

Here, r1 = 10 %, r2 = 20% and r3 = 30% ∴ Required discount = [1 - (1 - r1/100) (1 - r2/100) (1 - r3/100)] x 100% = [1 - (1 -10/100) (1 - 20/100) (1 - 30/100)] x 100% = {1 - (9/10) x (4/5) x (7/10)} x 100% = (1 - 0.504) x 100% = 49.6%