Let n be the total number of puffs. Now we can write:
\(n=\frac{5}{9}n+\frac{1}{3}n+18\)
Adding the fractional value of n, we get:
\(n=\frac{5+3}{9}n+18\)
Simplifying and rearranging gives us:
\(n-\frac{8}{9}n=18\)
Therefore we can simplify to get:
\(\frac{1}{9}n=18\)
and finally
\(n=18\times9=?\)
The fraction of the puff that are tuna is found from:
\(\frac{18}{18\times9}=\frac{1}{9}\)
