(b) 23
Suppose the number of students in each row = x
Then, number of students in each column = x + 3
⇒ x(x + 3) = 460 ⇒ x2 + 3x - 460 = 0
⇒ (x + 23)(x - 20) = 0 ⇒ x = - 23, 20
Rejecting negative value, number of students in each row = 20
∴ No. of students in each column = 23.