A dealer allows a discount of 10% and still gains by 10% what should be the marked price of the cost price is rs 900 ?

Given: A dealer allows a discount of 10% and still gains by 10%

To do: Find what should be the marked price of the cost price is Rs900

Solution:

Let the marked price be $x$.

Given cost price = 900.

Given that Discount = 10%. of $x$

SP = $x - 10% $of$ x$

 = $x - \frac{10}{100}x$

 =$ \frac{9x}{10}$           .............(i)

It also given that gain = 10%.

SP = $900 + 10%$ of $900$

     = $900 + \frac{10}{100} \times 900$

     = $900 + 90$

     =$ 990$.              .............(ii)

From i and ii

$990 = \frac{9x}{10}$

$x = 1100$.

So Marked price = 1100.