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Statement-1: Number of rectangles on a c...

Statement-1: Number of rectangles on a chessboard is `.^(8)C_(2)xx.^(8)C_(2)`.
Statement-2: To form a rectangle, we have to select any two of the horizontal lines and any two of the vertical lines.

A

Statement-1 is true, statement-2 is true, statement-2 is a correct explanation for statement-1

B

Statement-1 is true, statement-2 is true, statement-2 is not a correct explanation for statement-1

C

Statement-1 is true, statement-2 is false

D

Statement-1 is false, statement-2 is true

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the statements given about the number of rectangles that can be formed on a chessboard. ### Step-by-Step Solution: 1. **Understanding the Chessboard Structure**: - A standard chessboard is an 8x8 grid. This means there are 8 squares along each side. - To form rectangles, we need to consider the lines that define these squares. 2. **Counting the Lines**: - For an 8x8 chessboard, there are 9 horizontal lines (the lines above and below the squares) and 9 vertical lines (the lines to the left and right of the squares). - Hence, we have: - Horizontal lines = 9 - Vertical lines = 9 3. **Choosing Lines to Form Rectangles**: - To form a rectangle, we need to select 2 horizontal lines and 2 vertical lines. - The number of ways to choose 2 lines from 9 lines can be calculated using the combination formula \( nCk \), which is given by: \[ nCk = \frac{n!}{k!(n-k)!} \] 4. **Calculating the Combinations**: - For horizontal lines: \[ \text{Number of ways to choose 2 horizontal lines} = 9C2 = \frac{9!}{2!(9-2)!} = \frac{9 \times 8}{2 \times 1} = 36 \] - For vertical lines: \[ \text{Number of ways to choose 2 vertical lines} = 9C2 = 36 \] 5. **Total Number of Rectangles**: - The total number of rectangles formed is the product of the combinations of horizontal and vertical lines: \[ \text{Total rectangles} = 9C2 \times 9C2 = 36 \times 36 = 1296 \] 6. **Evaluating the Statements**: - **Statement 1**: The number of rectangles on a chessboard is \( 8C2 \times 8C2 \) - This is incorrect because we should be using \( 9C2 \) instead of \( 8C2 \). - **Statement 2**: To form a rectangle, we have to select any two of the horizontal lines and any two of the vertical lines - This is correct. ### Conclusion: - **Statement 1 is false** and **Statement 2 is true**.

To solve the problem, we need to analyze the statements given about the number of rectangles that can be formed on a chessboard. ### Step-by-Step Solution: 1. **Understanding the Chessboard Structure**: - A standard chessboard is an 8x8 grid. This means there are 8 squares along each side. - To form rectangles, we need to consider the lines that define these squares. ...
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ARIHANT MATHS ENGLISH-PERMUTATIONS AND COMBINATIONS -Exercise (Questions Asked In Previous 13 Years Exam)
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  2. There is a rectangular sheet of dimension (2m-1)xx(2n-1), (where m > 0...

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  3. If the letters of the word SACHIN are arranged in all possible ways...

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  5. At an election a voter may vote for nany number of candidates , not gr...

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  6. The letters of the word COCHIN are permuted and all the permutation...

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  7. The set S""=""{1,""2,""3,""........ ,""12) is to be partitioned into...

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  8. Consider all possible permutations of the letters of the word ENDEANOE...

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  9. How many different words can be formed by jumbling the letters in the ...

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  10. In a shop, there are five types of ice-creams available. A child buys ...

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  13. There are two urns. Urn A has 3 distinct red balls and urn B has 9 ...

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  14. Statement-1: The number of ways of distributing 10 identical balls in ...

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  15. There are 10 points in a plane, out of these 6 are collinear. The numb...

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  16. The total number of ways in which 5 balls of differert colours can be ...

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  17. Let n denote the number of all n-digit positive integers formed by the...

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  18. Let a(n) denote the number of all n-digit numbers formed by the digits...

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  19. Assuming the balls to be identical except for difference in colours, t...

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  20. Let Tn be the number of all possible triangles formed by joining ve...

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