Question

A zoo has 36 monkeys. Each male monkey needs 5 kg of food each day and each female needs 3 kg of food. The total amount of food available for these monkeys weighs 120 kg. How many male monkeys are there?

A) 12
B) 15
C) 18
D) 20

Answer 1

The question presents a typical system of linear equations word problem. By defining the number of male and female monkeys as variables and setting up two equations based on the given information, we solve the system to find that there are 6 male monkeys. However, this answer does not match any of the provided choices, indicating a possible error in the question or answer choices.

Step-by-step explanation:

Solving a Word Problem with a System of Equations

To find out how many male monkeys there are, we need to set up a system of equations based on the information provided. Let's define the number of male monkeys as 'm' and the number of female monkeys as 'f'. According to the question, there are a total of 36 monkeys, which gives us our first equation:

m + f = 36

Each male monkey needs 5 kg of food, while each female needs 3 kg. We're also told that the total food required is 120 kg. This gives us our second equation:

5m + 3f = 120

To solve the system, we can use the method of substitution or elimination. Let's multiply the first equation by 3, which will allow us to eliminate the variable 'f' when subtracted from the second equation:

3m + 3f = 108 (after multiplying the first equation by 3)

Now subtracting this from the second equation:

(5m + 3f) - (3m + 3f) = 120 - 108

2m = 12

Dividing both sides of the equation by 2, we get:

m = 6

So, there are 6 male monkeys.