Multiple choice

A shopkeeper gets a profit of 30% by selling a watch. If the shopkeeper buys the watch at 10% less than its price and sells it at 10% less than its selling price, the difference in the profit he makes is Rs. 300. Find the cost price of the watch?

  1. $10000$
  2. $20000$
  3. $1000$
  4. $5000$
  5. $7500$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let CP = x. Original: SP = 1.3x, profit = 0.3x. New: CP' = 0.9x, SP' = 0.9×1.3x = 1.17x, profit' = 0.27x. Difference: 0.3x - 0.27x = 0.03x = 300. Therefore x = 300÷0.03 = 10000. Answer A is correct. The key is understanding that profit difference is proportional to CP.