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Question
In a P.T. display, 480 students are arranged in rows and columns. If there are 4 more students in each row than the number of rows, find the number of students in each row.
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Solution
Let the number of rows be x
So, the number of students in each row = x + 4
Given, total students = 480
⇒ x(x + 4) = 480
⇒ x2 + 4x = 480
⇒ x2 + 4x − 480 = 0
⇒ x2 + 24x − 20x − 480 = 0
⇒ x(x + 24) −20(x + 24) = 0
⇒ (x − 20)(x + 24) = 0
⇒ x − 20 = 0 or x + 24 = 0
⇒ x = 20 or x = −24
Since number of rows cannot be negative hence, x ≠ -24.
If x = 20, x + 4 = 24.
Hence, the number of students in each row are 24.
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