Step 1 :
\Redraw the circuit with equivalent thevinins voltage and resistance.
\.gif\")
Observe the diagram.
\The resistors are connected in seies.
\
Thevenin
s voltage is 
Circuit current is
.
Substitute corresponding values in the above equation.
\
Step 2 :
\Maximum power will be transferred when source resistance and load resistances are equal.
\Maximum power dissipated is
.
Substitute
and
in the above equation.

Maximum power dissipated is
.
Solution :
\Maximum power dissipated is
.