The potential energy of a simple harmonic oscillator at mean position is $3$ joules. If its mean $K.E.$ is $4$ joules, its total energy will be : 

Energy at rest position is $3 J$ this is potential energy due to height, $mgh=3 J$

Mean $K.E.=4 J$

So maximum $K.E. =2$(Mean $K.E.$)$=8 J$

$T.E.=mgh+{\left(K.E.\right)}_{max}=3+8=11 J$