Question:medium
Some equations are solved on a certain basis. Find \(13 \times 13 = \,?\) given: \(5 \times 8 = 28,\; 3 \times 7 = 12,\; 8 \times 6 = 35.\)
Some equations are solved on a certain basis. Find \(13 \times 13 = \,?\) given: \(5 \times 8 = 28,\; 3 \times 7 = 12,\; 8 \times 6 = 35.\)
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Test simple transforms like \((a-1)(b-1)\) or \((a+1)(b+1)\) on all examples to uncover the rule.
Updated On: Aug 18, 2026
- 169
- 130
- 140
- 144
Show Solution
The Correct Option is D
Solution and Explanation
Step 1: Expand the coded pattern as \(ab-(a+b)+1\) and confirm it against the clues: \(5\times8\to28\), \(3\times7\to12\), \(8\times6\to35\).
Step 2: Apply the same expansion to \(13\times13\): \(169-(13+13)+1\).
Step 3: Simplify: \(169-26+1=144\).
\[ \boxed{144} \]
Step 2: Apply the same expansion to \(13\times13\): \(169-(13+13)+1\).
Step 3: Simplify: \(169-26+1=144\).
\[ \boxed{144} \]
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