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If the sum of two numbers is 41 and their product is 400. Then the numbers are ……………… A) 40, 10 B) 20, 20 C) 25, 16 D) 28, 13 |
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Answer» Correct option is (C) 25, 16 Let the numbers are a and b. Sum of numbers is 41. \(\therefore\) a+b = 41 __________(1) And product of the number is 400. \(\therefore\) ab = 400 __________(2) Now, \((a-b)^2=(a+b)^2-4ab\) \(=41^2-4\times400\) = 1681 - 1600 = 81 \(=9^2\) \(\Rightarrow\) a - b = 9 __________(3) By adding equations (1) & (3), we get (a+b) + (a - b) = 41+9 \(\Rightarrow\) 2a = 50 \(\Rightarrow\) a = \(\frac{50}2\) = 25 \(\therefore\) b = 41 - a (From (1)) = 41 - 25 = 16 Hence, required numbers are 25 and 16. Correct option is C) 25, 16 |
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