Given: Total number of heads = 52 Total number of legs = 158 Calculation: Let the number of birds and animals in the park be x and y respectively. Total number of heads = x + y = 52 ----(i) Total number of legs = 2x + 4y = 158 ⇒ (x + 2y) = 79 ----(2) From eq (1) and (2) (x + 2y) – (x + y) = 79 – 52 ⇒ y = 27 From eq (1) ⇒ x = 52 – 27 = 25 ∴ The number of birds in the park is 25