Question

Sipho and Litha are brothers. The sum of their ages is 29. In 6 years' time Sipho will be the same age as Litha was 3 years ago. Determine the current age of the two brothers. Let x be the age of Sipho.​

Answer 1

Sipho is 10 years old.

Litha is 19 years old.

Explanation:

We will use variables as their age.

x for Sipho

y for Litha

Here's what we know:

`x + y= 29`

`6 + x = y - 3`

Now we just need to isolate a variable in order to begin a system of equation.

`6 + x = y - 3 \\ + 3 \\ 9 + x = y`

Now that we have y in terms of x we just need to plug in

`x + y = 29 \\ x + (9 + x) = 29 \\ x + 9 + x = 29 \\ 2x + 9 = 29 \\ - 9 \\ 2x = 20 \\ / 2 \\ x = 10`

Now that we know x we now must find y.

`x + y = 29 \\ (10) + y = 29 \\ 10 + y = 29 \\ - 10 \\ y = 19`

We are done! Sipho is 10 years old and Litha is 19 years old.