What is the product of all the numbers on a standard telephone dial?

Difficulty: Medium

Correct Answer: None of these

Explanation:


Introduction / Context:
This question tests your logical observation about numbers on a standard telephone dial. A normal dial contains the digits from 0 to 9. The problem asks for the product of all these numbers. It is a quick test of whether you recognise how multiplication behaves when any factor is zero, rather than trying to perform unnecessary large multiplications.


Given Data / Assumptions:

  • A standard telephone dial has digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.
  • The product required is 0 * 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9.
  • We assume the dial is standard and includes 0.
  • We are not restricted to only non-zero digits unless explicitly stated, which is not the case here.


Concept / Approach:
The key concept is very simple: whenever you multiply any set of numbers and at least one of the factors is zero, the entire product becomes zero. Therefore, there is no need to calculate the factorial-like product of 1 through 9. Instead, you simply identify that 0 is included and conclude that the complete product equals zero. Then you check if zero is among the options; if not, the correct choice will be “None of these”.


Step-by-Step Solution:
Step 1: List the digits on a standard telephone dial: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.Step 2: The required product is 0 * 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9.Step 3: Recall that any number multiplied by 0 is 0.Step 4: Therefore, the entire product is 0, regardless of the values of the other digits.Step 5: Compare this result with the options and observe that none of the given numerical values equals 0.Step 6: Hence, the correct choice is “None of these”.


Verification / Alternative check:
If you ignore zero for a moment and compute the product of digits 1 through 9, you get 9 factorial, which is 362880. However, because 0 is part of the dial and is included in the product, the final product must be 0. None of the options matches 0 or 362880, which reinforces that the problem expects you to notice the presence of zero and to select “None of these”.


Why Other Options Are Wrong:
Option A (1,58,480), Option B (1,59,450), and Option C (1,59,480): These are arbitrary large numbers that might distract you into attempting long multiplications. None of them reflects the effect of multiplying by zero, and none equals the actual product.


Common Pitfalls:
A typical mistake is to start multiplying 1 * 2 * 3 and so on up to 9, completely overlooking the fact that 0 is included. This leads to wasted time and incorrect answers. Another pitfall is assuming the question might only involve digits 1 to 9 even though 0 is clearly part of a standard dial. Whenever you see a product including 0, immediately conclude that the result is 0 unless there is an explicit reason not to include that factor.


Final Answer:
The product of all the numbers on a standard telephone dial is 0, which is not listed among the given numbers, so the correct option is None of these.

More Questions from Arithmetic Reasoning

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion