FAA Aviation Mechanic General (AMG)Physics, Math and Fluid LinesMedium
A technician must prepare 5 gallons of cleaning solution using a concentrate that must make up 25% of the total mixture, with the remainder being water. How many gallons of concentrate are needed?
- A3.75 gal
- B0.25 gal
- C2.50 gal
- D1.25 gal
Show answer & explanationAnswer & explanation
Correct answer: D. 1.25 gal
The concentrate portion is 25% of the total 5 gallons: 5 × 0.25 = 1.25 gallons of concentrate, with the remaining 3.75 gallons being water.
Why the other options are wrong
- A. This is actually the water portion (75%), not the concentrate.
- B. This is 5% of the total, not 25%.
- C. This is 50% of the total, double the required amount.
Percentage Mixture Calculation
To find a component's quantity in a mixture, multiply the total volume by the required percentage expressed as a decimal.
- Convert percentage to decimal by dividing by 100
- Component volume = Total volume × decimal percentage
- Remaining volume = Total volume − component volume
Memory trick: 'Quarter of the whole' — 25% means take one-fourth of the total volume.