A fruit seller sells 40% of his apples and still has 420 apples left. How many apples did he originally have?
Aptitude
Percentage
Difficulty: Easy
Choose an option
Answer
Correct Answer: 700 apples
Explanation
Introduction / Context:This inventory question uses percentages of a whole. Selling 40% leaves 60% in stock. Knowing the remainder, we back-calculate the original stock using division by the remaining percentage.Given Data / Assumptions:
- Sold = 40% of original.
- Remaining = 420 apples = 60% of original.
Concept / Approach:If R = remaining and O = original, then R = 0.60O ⇒ O = R / 0.60. Use fraction 3/5 for faster mental math: O = 420 ÷ (3/5) = 420 * (5/3).Step-by-Step Solution:
Remaining fraction = 100% − 40% = 60% = 3/5.Original O = 420 ÷ (3/5) = 420 * (5/3).Compute 420/3 = 140; 140 * 5 = 700.Verification / Alternative check:Check: 40% of 700 = 280 sold; remaining = 700 − 280 = 420, which matches.
Why Other Options Are Wrong:
- 588, 600, 672: Do not yield 420 as 60% when tested.
Common Pitfalls:Using 40% instead of 60% for the remaining, or incorrectly converting percentages to fractions.
Final Answer:
700 apples