A man's wage was reduced by 50%. Again the reduced wage was increased by 50%. Find his loss in terms of percentage.
Numerical & Reasoning Ability ·Previously asked in JKSSB Constable (Executive / Armed / IRP / SDRF) 2024
View the full solved paper: JKSSB Constable 2024 - Set A
Question
A man's wage was reduced by 50%. Again the reduced wage was increased by 50%. Find his loss in terms of percentage.
- A. 25% (Correct answer)
- B. 30%
- C. 20%
- D. 35%
Correct Answer
Option A — 25%
Detailed Solution & Explanation
The correct answer is 25%.
Key Points
- Take the original wage as 100.
- After a 50% cut it becomes 50.
- A 50% rise on 50 adds 25, giving 75.
- The loss is 100 − 75 = 25, so the loss is 25%.
- A percentage decrease followed by an equal percentage increase never restores the original value, because the increase applies to a smaller base.
Additional Information
- For two successive percentage changes the net effect is x + y + (xy/100), taking decreases as negative.
- Here: −50 + 50 + (−50 × 50)/100 = −25, confirming the 25% loss directly.
- A general result worth remembering: an equal percentage decrease followed by an equal percentage increase always ends below the original, because the rise is applied to a smaller base. The same holds in reverse order.
- The loss for an equal x% down-then-up is always x²/100 percent — here 50²/100 = 25%.
Topics covered: Percentage Successive Change