A merchant purchases a wrist watch for ₹ 450 and fixes

A merchant purchases a wrist watch for ₹ 450 and fixes its list price in such a way that after allowing a discount of 10%, he earns a profit of 20%. Find the list price of the watch.

Let marked price of the wrist watch be p

∴	90p	=	450 × 120
	100		100

⇒ 90p = 450 × 120

∴ p =	450 × 120	= ₹ 600
	90

2nd method to solve this question.
Here, r₁ = 10%, profit = 20%,r = ?

Gain % =	r ×(100 − r₁)	− r₁
	100

20 =	r × (100 − 10)	− 10
	100

20 =	9r	− 10
	10

30 =	9r
	10

r =	300	%
	9

∴ List price = 450 + 450 ×	300	%
	9

List price = 450 + 450 ×	300
	900

Required List price = 450 + 150 = ₹ 600