This question asks us to find the selling price of a watch that ensures a 10% profit, given the initial selling price was Rs. 450 resulting in a 10% loss.
First, we need to determine the original cost price (CP) of the watch. We know that selling the watch for Rs. 450 resulted in a 10% loss.
The formula relating Selling Price (SP), Cost Price (CP), and Loss Percentage (Loss%) is:
SP = CP * (100 - Loss%) / 100
We are given:
Plugging these values into the formula:
Rs. 450 = CP * (100 - 10) / 100
Rs. 450 = CP * (90 / 100)
To find the CP, we rearrange the formula:
CP = Rs. 450 * (100 / 90)
CP = Rs. 450 * (10 / 9)
CP = Rs. 50 * 10
CP = Rs. 500
So, the cost price of the watch is Rs. 500.
Next, we need to find the selling price (let's call it SP') that would yield a 10% profit. We will use the cost price we just calculated (Rs. 500).
The formula relating Selling Price (SP), Cost Price (CP), and Profit Percentage (Profit%) is:
SP' = CP * (100 + Profit%) / 100
We have:
Plugging these values into the formula:
SP' = Rs. 500 * (100 + 10) / 100
SP' = Rs. 500 * (110 / 100)
SP' = Rs. 500 * (11 / 10)
SP' = Rs. 50 * 11
SP' = Rs. 550
Therefore, the watch should be sold for Rs. 550 to earn a 10% profit.