Question

the stidents of a class are made to stand in rows if three students are extra ina row, there would be one row less . if three students are less in a row, there would be 2rows more . find no. of students in a class

Answer 1

Let the number of rows be x .
Let no of students in each row be y .

So , total students = xy

Case 1) (y+3)(x-1) = xy
=> xy + 3x - y -3 = xy
=> 3x-y=3 –––(i)

Case 2) (y-3)(x+2)=xy
=> xy -3x-6+2y=xy
=> -3x+2y=6–––(ii)

So , by adding eq(i) & eq (ii)

we get , y= 9 & x=4
So , no of students =xy = 4×9 = 36 .