UPSC CSE Prelims 2021
Let the initial amounts of money with X, Y, and Z be represented by Rs. x, Rs. y, and Rs. z, respectively.
From the first condition, "If Y gives me Rs 40, then Y will have half of as much as Z":
The condition translates to the equation:
This simplifies to: (Equation 1)
From the second condition, "if Z gives me Rs 40, then three of us will have equal amount":
This condition implies that the amounts are equal:
From , we derive:
From , we derive: (Equation 2)
Now, substitute Equation 2 into Equation 1:
Rearranging the terms to solve for y:
Thus, Y has Rs. 120.
Using the value of y, calculate x and z:
Therefore, X has Rs. 80, Y has Rs. 120, and Z has Rs. 160.
The total amount of money X, Y, and Z have is the sum of their individual amounts:
Total =
The total amount is Rs. 360.
Options 1 (Rs 420), 3 (Rs 300), and 4 (Rs 270) are incorrect. The unique solution derived from the given conditions establishes the total amount as Rs. 360. Any other total would contradict the mathematical relationships specified in the problem statement.