Students of a class are made to stand in rows. If 3 students are extra in a row, there would be 2 rows less. If 4 students are less in a row, there would be 5 more rows. Find
the number of students in the class.

Let the number of rows be x and number of students in a row be y.

Total students of the class= Number of rows × Number of students in a row

=x×y=xy

Case 1

Total number of students =(x−1)(y+3)

⇒xy=(x−1)(y+3)=xy−y+3x−3

⇒3x−y−3=0

⇒3x−y=3 (i)

Case 2

Total number of students=(x+2)(y−3)

⇒xy=xy+2y−3x−6

⇒3x−2y=−6 (ii)

Subtracting equation (ii) from (i),

⇒(3x−y)−(3x−2y)=3−(−6)

⇒−y+2y=3+6

⇒y=9

By substituting value of y in (i), we get

⇒3x−9=3

⇒3x=9+3=12

⇒x=4

Number of rows =x=4

Number of students in a row =y=9

Number of total students in a class =x×y=4×9=36

Step-by-step explanation:

fist on the left goes with the third on the right. second on the left goes with the fourth on the right. third on the left goes with the second on the right. the fourth on the left goes with first on the right

c

step-by-step explanation: