Question

In a zoo, there are only deer and birds. Total heads = 36 and total legs = 100. How many birds are there?

• A. 20
• B. 16
• C. 18
• D. 22

Answer 1

Answer:

D. 22

Let:

• Deer = D (4 legs each)

• Birds = B (2 legs each)

Given:

• D + B = 36 (total heads)

• 4D + 2B = 100 (total legs)

From the first equation:

• B = 36 − D

Substitute into the second:

4D + 2(36 - D) = 100

4D + 72 - 2D = 100

2D = 28

D = 14

So,

B = 36 - 14 = 22

Answer: 22 birds