Question

In a deer park the number of heads and the number of legs of deer and visitors were counted and it was found that there were 39 heads and 132 legs. Find the number of deers and visitors in the park, using graphical method.

Answer 1

let x be the total no of legs of deer
let y be the total no of legs of visitors.
∴x + y = 132  
∵1deer has 4 legs and 1 head & 1 visitor has 2 legs and 1 head
∴x/4 + y/2 = 39
plotting the graph we get the point of intersection which is the value of x and y.
thus from the graph we can say x = 108 and y=24
∴ num of deers = 108/4 = 27
∴ num of visitors = 24/2 = 12

Answer 2

Let there be x deer and y human visitors in the park at the given time.

As a deer and a human each has one head, we get

x + y = 41

As a deer has 4 legs and a human has 2 legs, we get

4x + 2y = 136 = 2x + y = 68

Subtracting (i) from (ii), we get

x = 27.

Substituting x = 27 in (i), we get

27 + y = 41 = y = 14.

Hence, there were 27 deer and 14 human visitors in the park.