1]A single discount of 10%,20% and 40% is equal to a single discount of

a]50% b]56.8% c]60% d]70.28%
Net SP = [100-40%] of [100-20%] of [100-10%] of Rs.100
            = 60% of 80% of 90% of Rs.100
            = 60/100 * 80/100 * 90/100 * 100
            = 43.2
Required discount = 100 - 43.2 = 56.8

2]A single discount of 10%,20% and 5% is equal to a single discount of
a]31.6% b]31.5% c]31.4% d]31.3%

3]A single discount of 10%,12% and 15% is equal to a single discount of
a]50.2% b]67.32% c]60.8% d]70.28%

4]A single discount of 30% and 10% is equal to a single discount of
a]50% b]56% c]63% d]70%

5]A single discount of 20% and 30% is equal to a single discount of
a]50% b]56% c]60% d]70%

6]Two successive discounts of 20% and 15% are qual to a single discount of
a]50% b]68% c]60% d]70%

5]Two successive discounts of 20% and 10% are qual to a single discount of
a]50% b]56% c]60% d]72%