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

Explanation

Let the list price of the wrist watch is `x` rupees.

As, the merchant had given a discount of `10%` to the list price,

`:.` Selling price ` = x**(100-10)/100 = 0.9x` Rs

Now, Cost price of the wrist watch `= 450` Rs

Profit ` = 20%`

`:. 450**(100+20)/100 = 0.9x`

`=>450**120/100 = 0.9x`

`=>540 = 0.9x`

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