Instead of increasing a number by 25%, a student decreased that number by 25% and then increased the obtained number by 25%. By what percentage is the answer less than the original number?

Correct option is A

Given:
Original intended operation: Increase by 25%
Actual operations performed: Decrease by 25%, then increase by 25%
Formula Used:
Net Percentage Change = a + b + $$\frac{a × b}{100}$$​​
Solution:
Let the original number be 100.
Step 1: Decrease by 25%.
100 - 25 = 75
Step 2: Increase the obtained number by 25%.
75 + 75 × $$\frac{25}{100}$$​ = 75 + 18.75 = 93.75
The final number is 93.75, while the original number was 100.
Difference = 100 - 93.75 = 6.25
Percentage by which the answer is less than the original number:
$$\frac{6.25}{100}$$​ × 100 = 6.25%
Final Answer
So the correct answer is (a)