To gain 8% after allowing a discount of 10%, by what percent

To gain 8% after allowing a discount of 10%, by what percent cost price should be hiked in the list price ?

Let the cost price be ₹ 100 and marked price be p.

∴	p × 90	= 108
	100

⇒	9p	= 108
	10

⇒ p =	108 × 10	= 120
	9

Required Percent = 20%
2nd method to solve this question.
Here, Gain % = 8%,, r₁ = 10%, r = ?

Gain % =	r ×(100 − r₁)	− r₁
	100

8 =	r × (100 − 10)	− 10
	100

8 =	r × 90	− 10
	9

18 =	r × 9	= 20%
	9