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Tamil Nadu Board of Secondary EducationSSLC (English Medium) Class 10

The number of seats in a row is equal to the total number of rows in a hall. The total number of seats in the hall will increase by 375 if the number of rows is doubled and the number of seats in e - Mathematics

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Question

The number of seats in a row is equal to the total number of rows in a hall. The total number of seats in the hall will increase by 375 if the number of rows is doubled and the number of seats in each row is reduced by 5. Find the number of rows in the hall at the beginning.

Sum

Solution

Let the number of rows in the hall be “x”

∴ Total number of rows = x

Total number of seats in the hall is “x2

By the given condition

x2 + 375 = 2x (x – 5)

x2 + 375 = 2x2 – 10x

x2 – 2x2 + 10x + 375 = 0

– x2 + 10x + 375 = 0

– x– 10x – 375 = 0

(x – 25) (x + 15)

x – 25 = 0 or x + 15 = 0

x = 25 or x = – 15

Number of rows in the hall = 25

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Rational Expressions
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Chapter 3: Algebra - Unit Exercise – 3 [Page 157]

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Samacheer Kalvi Mathematics [English] Class 10 SSLC TN Board
Chapter 3 Algebra
Unit Exercise – 3 | Q 14 | Page 157
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