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A Two Digits Number is Such that the Product of the Digits is 12. When 36 is Added to the Number, the Digits Inter Change Their Places Determine the Number. - CBSE Class 10 - Mathematics

ConceptSolutions of Quadratic Equations by Factorization

Question

A two digits number is such that the product of the digits is 12. When 36 is added to the number, the digits inter change their places determine the number.

Solution

Let the tens digit be x

Then, the units digit = 12/x

therefore " Number" =10x+12/x

And, number obtained by interchanging the Digits = 10xx12/x+x=120/x+x

rArr10x+12/x+36=120/x+x

rArr9x+(12-120)/x+36=0

⇒ 9x2 - 108 + 36x = 0

⇒ 9(x2 + 4x - 12) = 0

⇒ x2 + 6x - 2x - 12 = 0

⇒ x(x + 6) - 2(x + 6) = 0

⇒ (x - 2)(x + 6) = 0

∴ x = 2 or x = -6

But, a digit can never be negative, x = 2

Hence, the digit =10x+12/x=10(2)+12/2=20+6=26

Is there an error in this question or solution?

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Solution A Two Digits Number is Such that the Product of the Digits is 12. When 36 is Added to the Number, the Digits Inter Change Their Places Determine the Number. Concept: Solutions of Quadratic Equations by Factorization.
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