The Apple Basket Puzzle is a brilliant test of logic and precision. It combines mathematical reasoning with clever deduction. You are given ten baskets of apples, but one basket contains lighter apples. With only one use of a digital scale, you must determine which basket it is.
This puzzle is popular in aptitude tests, coding interviews, and logical reasoning games because it requires critical thinking and number sense. At first glance, it seems impossible to solve with just one weighing, but the solution is surprisingly simple and elegant.
The Apple Basket Puzzle Setup and Rules
Here’s how the puzzle is set up:
- You have 10 baskets, each containing 10 apples.
- Normally, each apple weighs 10 grams.
- However, one basket contains apples that weigh only 9 grams each.
- You have an accurate digital scale, but you can use it only once.
The challenge:
Identify which basket contains the lighter apples using a single weighing.
How to Solve the Apple Basket Puzzle?
To solve this puzzle, you must think beyond direct weighing. Instead of comparing baskets, you use the weight difference as a hidden code that reveals the correct basket.
Let’s go step-by-step through the reasoning.
Step 1: Number the Baskets
Label the baskets from 1 to 10.
Each basket will now have a unique number: Basket 1, Basket 2, and so on.
This numbering is crucial because it helps track the source of the missing weight later.
Step 2: Select Apples Strategically
Instead of taking the same number of apples from each basket, take a different number of apples from each one.
Here’s how:
| Basket Number | Apples Taken |
|---|---|
| 1 | 1 apple |
| 2 | 2 apples |
| 3 | 3 apples |
| 4 | 4 apples |
| 5 | 5 apples |
| 6 | 6 apples |
| 7 | 7 apples |
| 8 | 8 apples |
| 9 | 9 apples |
| 10 | 10 apples |
In total, you will have 55 apples (1 + 2 + 3 + ... + 10 = 55).
Step 3: Weigh All the Apples Together
Now, place all 55 apples on the digital scale at once and note the total weight.
If all apples were normal (weighing 10 grams each), the total weight would be:
Expected Weight = 55 × 10 = 550 grams.
Step 4: Observe and Compare the Weight
But since one basket has lighter apples (9 grams each), the actual total weight will be less than 550 grams.
The difference between expected weight (550 g) and actual weight (observed on scale) reveals the number of the lighter basket.
Step 5: Identify the Basket with Lighter Apples
Every missing gram corresponds directly to the basket number containing the lighter apples.
| Total Weight (grams) | Difference from 550 | Basket with Lighter Apples |
|---|---|---|
| 549 | 1 | Basket 1 |
| 548 | 2 | Basket 2 |
| 547 | 3 | Basket 3 |
| 546 | 4 | Basket 4 |
| 545 | 5 | Basket 5 |
| 544 | 6 | Basket 6 |
| 543 | 7 | Basket 7 |
| 542 | 8 | Basket 8 |
| 541 | 9 | Basket 9 |
| 540 | 10 | Basket 10 |
Example:
If the scale shows 546 grams, that’s 4 grams less than expected.
That means Basket 4 contains the lighter apples.
Why This Method Works?
The key idea is that each basket contributes a unique, measurable difference to the total weight. Because the number of apples taken from each basket corresponds to its number, the missing grams directly identify the faulty basket. You’re not comparing apples; you’re encoding each basket into the total weight using mathematics.
Final Answer:
The basket with lighter apples can be found by this formula:
Basket Number = 550 – (Actual Weight)
This puzzle elegantly shows how logical planning and numerical reasoning can turn a single measurement into a powerful source of information.
Why the Apple Basket Puzzle is Popular?
The Apple Basket Puzzle is widely used to test analytical thinking and pattern recognition. It’s not about complex math but smart thinking, how to use limited resources to get maximum information.
It is a favorite among:
- Tech interviews (Google, Amazon, Microsoft).
- IQ and reasoning tests.
- Educational puzzle books and online quizzes.
This puzzle highlights how mathematical logic can solve problems that at first seem impossible.
Similar Logic Puzzles with Answers
If you enjoyed solving the Apple Basket Puzzle, here are some other famous logic puzzles that use the same kind of reasoning and strategy.
1. The 100 Prisoners Hat Puzzle – Logic and Parity
Setup: 100 prisoners must guess the color of their hat using a pre-decided plan.
Answer: Using parity logic, 99 prisoners survive for sure, and sometimes all 100 do.
2. The River Crossing Puzzle – Farmer, Goat, Wolf, and Cabbage
Setup: A farmer must cross a river with a wolf, goat, and cabbage without anyone getting eaten.
Answer: The correct sequence - Goat → Wolf → Cabbage → Goat - gets everyone across safely.
3. The Blue Eyes Puzzle – Logical Deduction
Setup: People on an island must determine their eye color without direct communication.
Answer: If n people have blue eyes, they all leave on the nth night after the announcement.
4. The Two Doors Riddle – Truth and Lies
Setup: Two guards protect two doors: one leads to safety, one to death.
Answer: Ask, “If I asked the other guard which door leads to freedom, what would he say?” Then take the opposite door.
5. The Monty Hall Problem – Probability and Choice
Setup: You choose one of three doors. Behind one is a car; behind the others are goats. One goat door is revealed.
Answer: Always switch. Your chance of winning increases from 1/3 to 2/3.