The (''psi'') particle has a rest energy of 3097MeV (1 MeV = 106eV). The particle is unstable

Question:

The ψ (''psi'') particle has a rest energy of 3097MeV (1 MeV = 106eV). The ψ particle is unstable with a lifetime of 7.6 x 10-21s. Estimate the uncertainty in rest energy of the ψ particle. Express your answer in MeV and as a fraction of the rest energy of the particle.