Correct Answer - Option 1 : Rs. 50
Given :
Gopal sold his watch for Rs. 75 and got a percentage of profit equal to the cost price.
Calculations :
Let the cost price be C
Now according to the question
C = (75 - C)/(C) × 100
⇒ C2 = 7500 - 100C
⇒ C2 - 7500 + 100C = 0
⇒ (C - 50) (C + 150) = 0
⇒ C = 50
∴ Option 1 is the correct answer.