ASVAB (Armed Services Vocational Aptitude Battery)Mathematics Knowledge (MK)Hard
A medical specialist needs to dilute a concentrated solution. If 20 ml of a 75% antiseptic solution is mixed with 30 ml of water, what is the percentage concentration of the new solution?
- A35%
- B30%
- C45%
- D40%
Show answer & explanationAnswer & explanation
Correct answer: B. 30%
First, calculate the amount of antiseptic in the concentrated solution: 20 ml * 0.75 = 15 ml. Then, calculate the total volume of the new solution: 20 ml (antiseptic solution) + 30 ml (water) = 50 ml. Finally, calculate the new concentration: (15 ml antiseptic / 50 ml total solution) * 100% = 0.3 * 100% = 30%.
Why the other options are wrong
- A. Possible error in total volume or calculation.
- C. Significant calculation error or misunderstanding of dilution.
- D. Error in initial amount of antiseptic or total volume.
Solution Dilution Calculation
Dilution calculations involve determining the new concentration of a solution after adding more solvent. The amount of solute remains constant, but the total volume increases.
- Amount of solute = Volume of concentrated solution × Concentration.
- Total volume = Volume of concentrated solution + Volume of solvent added.
- New concentration = (Amount of solute / Total volume) × 100%.
Memory trick: Solute 'S'tays, 'V'olume 'V'aries, 'C'oncentration 'C'alculated.