Sipho is 4 years older than his sister.Their combined age is 18.How old is sipho?

s + s + 4 = 18

2s = 14
s = 7

The sister is 7 years old.

Sipho=4x

Sister=x

x+x+4=18
2x=14
x=7

4(7)=28

What is this?

4(7)=28

To find Sipho's age, we can set up a system of equations. Let's use the variable "s" to represent Sipho's age and "x" to represent his sister's age.

We know that Sipho is 4 years older than his sister, so we can write the equation:

s = x + 4

We also know that their combined age is 18, so we can write the equation:

s + x = 18

Now, we can solve this system of equations to find Sipho's age.

Substitute the value of s from the first equation into the second equation:

x + 4 + x = 18

Combine like terms:

2x + 4 = 18

Subtract 4 from both sides:

2x = 14

Divide both sides by 2:

x = 7

Now that we know his sister's age is 7, we can substitute this value back into the first equation to find Sipho's age:

s = x + 4 = 7 + 4 = 11

Therefore, Sipho is 11 years old.