Fred said,"Each of my sons has twice as many sisters as he has brothers and each daughter has the same number of brothers as she has sisters."

How many sons and daughters does Fred have?

3 sons 4 daughters

设x为姐妹,y为兄弟

x=y
x=2y
-x=1=y
-2=x=2y=1
所以兄弟x为4,姐妹y为3

To solve this problem, we can use algebraic equations. Let's assign variables to the unknowns:

Let x represent the number of sons that Fred has.
Let y represent the number of daughters that Fred has.

According to the given information, each son has twice as many sisters as brothers. This can be written as:

2(x - 1) = y

This equation represents that each son (x - 1 because it doesn't count the son himself) has twice the number of sisters (y) as brothers (x).

Additionally, each daughter has an equal number of brothers and sisters. This can be written as:

x = y

Now, we can solve the system of equations to find the values of x and y.

From the equation x = y, we can substitute x in the first equation:

2(x - 1) = x

Using basic algebra, we can solve for x:

2x - 2 = x
x = 2

Now that we know x = 2, we can substitute this value into the second equation to find y:

2 = y

Therefore, Fred has 2 sons and 2 daughters.