Question

Mr Chong intends to purchase a few chickens, rabbits and ducks for his farm. The total numbers of animal is 50. He has RM1500 to be spent. A chicken costs RM20, A rabbit RM50 and a duck RM30. The number of chickens is equal to the number of ducks. How many of each animals should Mr Chong purchase? Write a system of linear equations to solve this problem.

Answer 1

20 chickens, 10 rabbits and 20 ducks

Explanation:

Let chickens be c, rabbits be r, ducks be d

• Chicken cost = RM20
• Rabbit cost = RM50
• Duck cost = RM30

As per given we get below equations:

• c + r + d = 50
• c = d
• 20c + 50r + 30d = 1500

Substitute d:

• c + r + c= 50 ⇒ 2c + r = 50

• 20c + 50r + 30c = 1500 ⇒ 50c + 50r = 1500 ⇒ c + r = 30

Subtract the second equation from the first one:

• c = 20

Then:

• r = 10
• d = 20

So animals bought:

• 20 chickens, 10 rabbits and 20 ducks