the student of a class are made to stand in a row ..iff three student are extra in a row ther would be 1;row less ..if three students are less ina row ,there would be two rows more ..find the number of students in the class
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hopebu give rigjt answer and will take the reward of brainlist answer.
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Let the number of rows = y.
The total number of students = xy.
Given that if three students are extra in a row would be 1 row less.
Then the total number of students = (x - 1)(y + 3).
xy = (x - 1)(y + 3)
xy = xy + 3x - y - 3
3x - y = 3. ----- (1)
Given that if three students are less in a row, there would be two rows more.
Then the total number of students = (x + 2)(y - 3)
xy = (x + 2)(y - 3)
xy = xy - 3x + 2y - 6
3x - 2y = -6 -------- (2)
On Solving (1) & (2), we get
3x - 2y = -6
3x - y = 3
--------------------
-y = -9
y = 9
Substitute y = 9 in (2), we get
3x - 2(9) = -6
3x - 18 = -6
3x = -6 + 18
3x = 12
x = 4.
Hence the number of rows = 4.
Hence the number of students = 9.
Therefore the number of students in the class = 4 * 9
= 36.
Hope this helps!
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Let the no. of rows be x
And the no. of students in the row be y.
So,
No. of students in the class = xy
A/Q,
Total no. of students = ( x-1 ) ( y+3)
=> xy = ( x-1 ) ( y+3 )
=> xy = x ( y+3 ) -1 ( y+3 )
=> xy = xy + 3x - y - 3
=> 3x - y - 3 = 0
=> 3x - y = 3.........(1)
Again,
Total no. of students = ( x+2 )( y-3 )
=> xy = x ( y-3 ) + 2 ( y-3 )
=> xy = xy - 3x + 2y -6
=> 3x - 2y = -6.........(2)
Subtracting equation (2) from (1), we obtain:
y = 9
Substituting the value of y in equation (1), we obtain:
=> 3x – 9 = 3
=> 3x = 9 + 3 = 12
=> x = 4
Thus,
Number of rows = x = 4
Number of students in a row = y = 9
So,
Total no. of students in the class , xy
= ( 9×4 )
= 36
Hope it helps !!!