Let the x and y denote number of snakes and lizards.
Since snakes have no legs and lizards have 4 legs. So the equation can be written as
0x + 4y = 24
=> 4y = 24
=> y = 6 --------------------------(1)
Also, both snakes and lizards have one tail. Therefore the equation can be formed as
x + y = 24
=> x = 24 - y
=> x = 24 - 6 (from equation 1)
=> x = 18
So there are total of 18 snakes in the section of the zoo.