lander=1.2*10^12
muon mass=207*9.11*10^-31
muon speed=3*10^6
neutral pion mass=134.972
calculate the speed necessary for a (neutral pion) to have the same de Broglie wavelength as that of the muon (lander)
the mark scheme uses the conservation of momentum, MV(of pion)=MV(of muon)
yet it ends up with (3*10^6)/1.28 (1.28 is the ratio (rest mass pion)/(rest mass muon))
I don't understand how it gets this please help quick