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.

Answer 1

GIVEN : Total numbers of students in a P.T display = 480

Let the number of columns be x & number of rows (x+4)

ATQ
x (x+4) = 480
x² +4x =480
x² +4x - 480 = 0
x² +24x -20x - 480= 0
[ by factorization method]
x(x + 24) -20(x + 24) = 0
(x+24) (x-20) = 0
x+24 = 0 or x-20 = 0
x = -24 or x = 20
But x = -24 is not possible because number of rows can't be negative.
Therefore , x = 20
Number of columns = 20
number of rows = x +4 = 20 + 4 = 24

Hence, the number of rows is 24.

HOPE THIS WILL HELP YOU….

Answer 2

heya..!!!


let the no. of coloumn be x
and rows be (x + 4)

according to question

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 , x = -24 [neglect]

NOW x = 20 = coloumn
AND rows be (20 + 4) = 24