Functions and Integration

If $f(x)$ and $\phi(x)$ are continuous functions on the interval $[0,6]$ satisfying $f(x)=f(6-x)$ and $\phi(x)+f(6-x)=5$ and $\displaystyle \int _{0}^{6} f(x)=3$ then the value of

$\large{\{\displaystyle \int ^{6}_{0} f(x) \phi(x) .dx\}}$

where $\{x\}$ denotes fractional part of $x$