Final answer:
To calculate the cost of the sofa set, divide the selling price by 1 plus the profit percentage. For a profit of 10%, the cost of the sofa set is Rs. 10909.09. To calculate the selling price for a profit of 20%, multiply the cost price by 1 plus the profit percentage. The selling price would be Rs. 13090.90.
Step-by-step explanation:
To calculate the cost of the sofa set, we can use the formula:
Cost price = Selling price / (1 + Profit percent)
Given that Sara sold her sofa set for Rs. 12000 making a profit of 10%, we can substitute the values into the formula:
Cost price = 12000 / (1 + 0.10) = 12000 / 1.10 = Rs. 10909.09
So, the cost of the sofa set for Sara was Rs. 10909.09.
To calculate the selling price for a profit of 20%, we can use the formula:
Selling price = Cost price * (1 + Profit percent)
Substituting the values, we get:
Selling price = 10909.09 * (1 + 0.20) = 10909.09 * 1.20 = Rs. 13090.90
Therefore, Sara should sell the sofa set for Rs. 13090.90 to make a profit of 20%.