A boy sold his cap for Rs. 24 and got a profit percentage numerically equal to the cost price. What will be the cost price of the cap?

A boy sold his cap for Rs. 24 and got a profit percentage numerically equal to the cost price. What will be the cost price of the cap? Correct Answer Rs. 20

Given 

The selling price of cap = Rs 24 

Formula Used 

Cost price = {Selling Price/(100 + profit%)} × 100 

Calculation 

Let the cost price be x 

⇒ x = 24/(100 + x) × 100 

⇒ x2 + 100x - 2400 = 0 

⇒ x2 + 120x - 20x - 2400 = 0

⇒ x(x + 120) - 20(x + 120) =

⇒ (x - 20)( x + 120)

We get x = 20 and x = - 120

(As cost price cannot be negitive)

So, cost price = Rs 20 

∴ The cost price is Rs 20

Related Questions

Each question below is followed by two statements I and II. You have to determine whether the data given in the statements are sufficient for answering the question. You should use the data and your knowledge of Mathematics to choose the best possible answer. The combined cost of three articles in a shop is Rs.4200. Two article sold at profit of 25% and 12.5% and third article is sold such that there is a loss of Rs.630. What is the loss percentage incurred on third article. I. The difference between cost price of highest article and lowest article is Rs.600. The costliest article is sold at a loss.  II, The cheapest item is sold at 25% profit. The the price of one of that article is the average price of the cheapest and costliest item.