Now let the marked price be x
We are given that the product was sold with a discount of 10 %
Hence we know that
Discount = 10% of MP
\(\Rightarrow Discount = \frac {10}{100} \times x = \frac {x}{10}\)
Whenever a discount a given our selling price is given by
⇒ SP = MP - Discount
⇒ \(SP = x - \frac {x}{10}\)
⇒ \(SP = \frac {10x-x}{10} = \frac {9x}{10}\)
It is also given that the person gains 10% on selling the product.
The gain is nothing other than 10% of the price with which he brought the product.
⇒ Gain = 10% of CP
⇒ Gain = \(\frac {10}{100} \times 900 = 90\)
Hence we get that the person gains Rs.90 on selling the product
We also know that
⇒ Gain = SP - CP
Using the known values we get
\( \Rightarrow 90=\frac{9 x}{10}-900 \)
\(\Rightarrow 90=\frac{9 x-9000}{10} \)
\(\Rightarrow 900=9 x-9000 \)
\(\Rightarrow 900+9000=9 x \)
\(\Rightarrow 9900=9 x \)
\( \Rightarrow \frac{9900}{9}=x \)
\(\Rightarrow x=1100\)
Now we get the value of x
And hence the marked price is Rs.1100.