ASVAB (Armed Services Vocational Aptitude Battery)Arithmetic Reasoning (AR)Hard
A medical unit has 120 doses of a vaccine. If 3/4 of the doses are administered on the first day, and then 1/2 of the remaining doses are administered on the second day, how many doses are left?
- A45 doses
- B60 doses
- C15 doses
- D30 doses
Show answer & explanationAnswer & explanation
Correct answer: C. 15 doses
First, calculate the doses administered on day 1 (3/4 of 120). Subtract this from the total to find the remaining doses. Then, calculate 1/2 of those remaining doses for day 2. Subtract day 2 doses to find the final amount left.
Why the other options are wrong
- A. This is an incorrect calculation.
- B. This might be the amount administered on day 1, or an incorrect calculation.
- D. This is the amount remaining after the first day, not after both days.
Successive Fractional Reduction
To calculate the final amount after multiple fractional reductions, first calculate and subtract the initial reduction, then calculate and subtract the subsequent reduction from the new total.
- Each fraction applies to the *current* remaining amount, not the original total.
- Involves multiple steps of multiplication and subtraction.
- Order of operations is crucial.
Memory trick: First fraction, then what's left, then second fraction, then final theft!