Answer:
Portion of tax burden shared by buyers (consumers) & sellers will be equal, ie half half each.
Explanation:
When an indirect tax, whose burden & incidence are on different people, (like excise tax) is levied : Its burden is borne more by buyers if demand is relatively more inelastic (or less elastic), & more by sellers if supply is relatively less inelastic (or less elastic).
Given, price elasticity of demand & supply both = 2 respectively. So, excise tax burden is shared by both buyer & sellers equally, as both demand & supply are equally price elastic.