The students of a class are made to stand in rows. If 4 students are extra in a row, there would be 2 rows less. If 4 students are less in a row, there would be 4 rows more. Find the number of students in the class.
Let the number of students in each row be x and the number of rows be y.
So, the total number of students is x × y.
First condition:
If 4 students are added to each row, the number of rows becomes 2 less.
This gives the equation:
(x + 4)(y - 2) = x × y
=> xy - 2x + 4y - 8 = xy
=> -2x + 4y = 8 ------------------------------------ (1)
Second condition:
If 4 students are removed from each row, the number of rows becomes 4 more.
This gives the equation:
(x - 4)(y + 4) = x × y
=> xy + 4x - 4y - 16 = xy
=> 4x - 4y = 16 ---------------------------------- (2)
Now add both equations:
(−2x + 4x) + (4y − 4y) = 8 + 16
=> 2x = 24 => x = 12
Now put x = 12 into Equation 1:
−2(12) + 4y = 8
=> −24 + 4y = 8
=> 4y = 32 => y = 8
Hence Students in each row = 12 & Number of rows = 8
Total students = 12 × 8 = 96
So, there are 96 students in the class.
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