Which is the substance dat is oxidised & reduced ? :
2KMnO4 --> K2MnO4 + MnO2 + O2
??
( THANKZ ALOOT )
You may want to rewrite the equation as
KMnO4 + KMnO4 ==> K2MnO4 + MnO2 + O2
Remember that oxidation is the loss of electrons. Reduction is the the gain of electrons. I would focus my attention on Mn and O