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The Product of Ramu'S Age (In Years) Five Years Ago and His Age (In Years) Nice Years Later is 15. Determine Ramu'S Present Age. - Mathematics

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Question

The product of Ramu's age (in years) five years ago and his age (in years) nice years later is 15. Determine Ramu's present age.

Solution

Let the present age of Ramu be x years

Then, 9 years later, age of her = (x + 9) years

Five years ago, her age = (x - 5) years

Then according to question,

(x - 5)(x + 9) = 15

x2 + 9x - 5x - 45 = 15

x2 + 4x - 45 - 15 = 0

x2 + 4x - 60 = 0

x2 - 6x + 10x - 60 = 0

x(x - 6) + 10(x - 6) = 0

(x - 6)(x + 10) = 0

So, either 

x - 6 = 0

x = 6

Or

x + 10 = 0

x = -10

But the age never be negative

Hence, the present age of Ramu be 6 years.

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Chapter 4: Quadratic Equations - Exercise 4.9 [Page 61]

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RD Sharma Mathematics [English] Class 10
Chapter 4 Quadratic Equations
Exercise 4.9 | Q 4 | Page 61
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