Profit = 8%
If the briefcase was marked down 20% from 1500 you multiply 1500 x .2 = 300 in order to calculate the discount.
Calculate the discounted price:
1500 - 300 = 1200
Calculate 10% discount of 1200:
1200 x .1 = 120
Calculate the sales price:
1200 - 120 = 1080
The last step is to calculate the profit/loss is the cost is 1000.
The briefcase sold for 1080 and the company paid 1000 for it, so there was a profit of 80.
The percentage is calculate by dividing 80/1000 = 8% profit