Let your age be 'X'
Then the age of your brother will be
[tex] \frac{1}{3} x[/tex]
The age of your sister is 10, but can also be written as an expression (since it is the age of your brother +6)
[tex] \frac{1}{3} x + 6 [/tex]
Now we get the following equation:
[tex] \frac{1}{3} x + 6 = 10[/tex]
Subtract 6 from both sides
[tex] \frac{1}{3} x = 4[/tex]
Multiply by 3
[tex]x = 12[/tex]
Hence, the answer on your question (which is your age) is 12.
