A dealer marks his goods 20% above the cost price. He then allows some discount and makes a profit of 8%. The rate of discount is

The discount rate is 10%.

Take cost price = 100; marked price = 100 + 20% = 120.

Profit is 8%, so selling price = 108.

Discount = marked - selling = 120 - 108 = 12.

Discount rate = 12 / 120 x 100.

12 / 120 x 100 = 10%.