A mobile company offered to pay the Indian Cricket Team as much money per run scored by the side as the total number it gets in a one-dayer against Australia. Which one of the following cannot be the total amount to be spent by the company in this deal?
Aptitude
Square Root and Cube Root
Difficulty: Easy
Choose an option
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A21,904
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B56,169
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C1,01,761
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D1,21,108
Answer
Correct Answer: 1,21,108
Explanation
Concept & Logic
The company pays an amount equal to the number of runs multiplied by the number of runs. Thus, the total amount spent must be a perfect square. The question is asking us to identify the single option that is **not** a perfect square.
Step-by-Step Solution
* **Given**: Total amount = (Runs Scored) $\times$ (Runs Scored) = $R^2$.
* We need to inspect the unit digits of the given options to rule out non-perfect squares.
* A fundamental rule of mathematics: A perfect square can never end in $2$, $3$, $7$, or $8$.
* Let us check the last digit of each given option:
- Option (a) $21,904$ ends in $4$ (possible perfect square).
- Option (b) $56,169$ ends in $9$ (possible perfect square).
- Option (c) $1,01,761$ ends in $1$ (possible perfect square).
- Option (d) $1,21,108$ ends in $8$ (impossible).
* Since no integer squared ends in $8$, $1,21,108$ mathematically cannot be the total amount spent.
Exam Strategy & Shortcut
Always check the unit digits first when asked if a number is a perfect square! Perfect squares only end in $0, 1, 4, 5, 6,$ or $9$. Option (d) ends in $8$, making it instantly incorrect as a perfect square. Absolutely no calculation is required.
Common Pitfall
Wasting valuable exam time trying to calculate the exact square root of each large 5- or 6-digit number. Recognizing unit digit rules saves massive amounts of time on these types of questions.
Final Answer
**Therefore, the correct answer is 1,21,108.**