Ronald has 15 animals his barn, made up of cows x) and turkeys ). Ronald knows that there are 30 legs in total How many cows are in the barn?

Answer 1

Hi Ronald,

this is a system of equations problem.

first you have a total of 15 animals made up of turkeys and cows.

So

x = turkey

y = cows

x + y=15

then

value turkey has 2 legs

Cow has 4 legs

second equation

2 x + 4y= 30

muse either substitution or elimination.

to solve.

Hope this helps

Answer 2

Hi Ana,

This is a substitution problem.

Let's start by forming 2 equations based on the info provided.

Let x be the # of cows.

Let y be the # of turkeys.

15 animals, made up of cows and turkeys. Therefore, the first equation is x + y = 15

There are 30 legs in total. We know cow has 4 legs and turkey has 2 leg.

Therefore, the second equation is 4x + 2y = 30

So we just formed two equations:

x + y = 15

4x + 2y = 30

The problem ask for the the # of cows, which is x.

We will manipulate one of the equation, and I'll pick the first one for easy measure.

x + y = 15. This also mean x = 15 - y

Then, we'll use our new equation x = 15 - y and plug it in the 'x' value of the second equation.

4x + 2y = 30

4(15-y) + 2y = 30

You should get y to be 15. This is mean that there is 15 turkey in the barn, and as a result, 0 cow.

You can also switch it and use y = 15 - x as well, as another way to solve this question.

4x + 2y = 30

4x + 2(15 - x) = 30 and this gives us the answer of 0 for x, which means there is 0 cow.

Maybe this is a question being done on purpose to trick you but by using math, you can be sure of this bizarre answer.

Hope this helps!

Answer 3

The total number of cows, x, and turkeys, y is:

x+y=15

Also, each cow has 4 legs and each turkey has 2, so the total number of legs is:

4x+2y=30

Now we want to solve for the number of cows, x, so we must solve for the number of turkeys, y, in the first equation, then substitute it into the second equation. Solving for y in the first equation by subtracting x from both sides:

y=15-x

Now, substituting the expression for y into the second equation:

4x+2(15-x)=30

Distributing the 2, combining the x terms, subtracting 30 from both sides, then dividing both sides by 2:

4x+30-2x=30

2x+30=30

2x=0

x=0

The number of cows is 0. There are no cows!