ASVAB (Armed Services Vocational Aptitude Battery)Arithmetic Reasoning (AR)Medium
A supply depot has 12,000 gallons of fuel. They use 1/4 of it in the first week and then 1/3 of the *remaining* fuel in the second week. How many gallons of fuel are left after the second week?
- A6000 gallons
- B4000 gallons
- C8000 gallons
- D5000 gallons
Show answer & explanationAnswer & explanation
Correct answer: A. 6000 gallons
First week's usage: (1/4) * 12,000 gallons = 3,000 gallons. Remaining fuel after week 1: 12,000 - 3,000 = 9,000 gallons. Second week's usage (1/3 of remaining): (1/3) * 9,000 gallons = 3,000 gallons. Fuel left after week 2: 9,000 - 3,000 = 6,000 gallons.
Why the other options are wrong
- B. Incorrect calculation, possibly if 1/3 of original total was used in week 2.
- C. This would be the remaining fuel if only 1/4 was used in total.
- D. Incorrect calculation, likely arithmetic error.
Successive Fractional Reduction
Problems where a fraction of a quantity is removed, and then a fraction of the *new remaining* quantity is removed.
- Calculate the amount removed in the first step.
- Subtract to find the new remaining quantity.
- Calculate the fraction of this *new remaining* quantity for the next step.
- Continue this process until the final remaining amount is found.
Memory trick: Subtract and Recalculate: Take out a piece, then take from what's left.