Question

When a shopkeeper gives discount 10% on the list price of toy then his gain percent is 20% but if he had given 20% discount then what is gain percent

Answer 1

 Let List Price  be X
Sale Price = 0.9X
He earns 20% profit after selling at 0.9X
Hence the cost price= 0.9X100/120=0.75 X
when he gives 20% discount the sale price is 0.8X
Hence gain percent = (Sale Price - cost price)100 /cost price
                             = (0.8X - 0.75X)100/0.75X
                             = 6.66%
His gain is 6.66%