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In a Zoo; there are hens and goats. If heads are counted, there are 40 and if legs are counted, there are 100. How many hens are there?

In a Zoo; there are hens and goats. If heads are counted, there are 40 and if legs are counted, there are 100. How many hens are there? Correct Answer 30

Given:

Number of heads = 40

Number of legs = 100

Calculation:

Let the number of hens be x and number of goat be y

If he counted head

⇒ x + y = 40       ----(1)

If legs are counted, hens has 2 legs and goat has 4 legs

⇒ 2x + 4y = 100       ----(2)

Multiply by 4 in equation 1

⇒ 4x + 4y = 160       ----(3)

Subtract equation 2 from equation 3

⇒ 2x = 60

⇒ x = 30

∴ Hens are there 30 hens.

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