GRE General TestQuantitative ReasoningEasy
A software engineer is debugging a program. The program takes 30 minutes to compile on a standard machine. If a new, faster machine can compile the program 25% quicker, how many minutes will it take to compile on the new machine?
- A37.5
- B7.5
- C24.0
- D22.5
Show answer & explanationAnswer & explanation
Correct answer: D. 22.5
A 25% quicker compilation means the time is reduced by 25%. Calculate 25% of the original time and subtract it from the original time, or multiply the original time by (1 - 0.25).
Why the other options are wrong
- A. This is the result of adding 25% of the time, not subtracting it.
- B. This is 25% of the original time, not the reduced time.
- C. This is incorrect; likely a miscalculation or misinterpretation of '25% quicker'.
Percentage Decrease
Reducing a quantity by a certain percentage, where the decrease is calculated based on the original quantity.
- To decrease by P percent, calculate P/100 * Original Value.
- New Value = Original Value - (P/100 * Original Value).
- Alternatively, New Value = Original Value * (1 - P/100).
Memory trick: Original Minus Percent: Subtract the percentage portion from the starting amount.