ans: The real cost of the item sold is 20,000 TK

Let, the cost price be = 100 Tk.

At 10% profit the market price of the product will be = 100 + 10 = 110 Tk.

At 5% loss, the selling price will be = 110 – 5% of 110

= 110 – $\frac{110\times 5}{100}$

= 110 -$\frac{11}{2}$

= 110 -5.5

= 104.5

Profit = (104.5 – 100) Tk. = 4.5 Tk.

Dishonest merchant makes 4.5 Tk. profit while cost price = 100 Tk.

Dishonest merchant makes 1 Tk. profit while cost price = $\frac{100}{4.5}$ Tk.

Dishonest merchant makes 900 Tk. profit while cost price =$\frac{100\times 900}{4.5}$= 20,000 Tk.