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The ratio between the two digit number and two digit number obtained by interchanging digits is 9 : 2. The sum of two digits of number is 9. Find the two digit number.1. 272. 363. 724. 185. 81 |
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Answer» Correct Answer - Option 5 : 81 Given: The ratio between the two digit number and two digit number obtained by interchanging digits is 9 : 2 Calculation: Let two digit number be 10a + b. The two digit number obtained after reversing it's digit = 10b + a ⇒ (10a + b) : (10b + a) = 9 : 2 ⇒ 20a + 2b = 90b + 9a ⇒ 11a = 88b ⇒ a = 8b Then, ⇒ a + b = 9 Solving, a = 8 and b = 1 Two digit number = 10a + b = 81 Therefore the correct answer is 81. |
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