Assume that ExxonMobil uses a standard cost system for each of its refineries. For the Houston refinery, the monthly fixed overhead budget is $$9,900,000$ for a planned output of $6,000,000$ barrels. For September, the actual fixed cost was $$10,115,000$ for $5,950,000$ barrels.

a$.$ Determine the fixed overhead budget variance.

b$.$ If fixed overhead is applied on a per$-$barrel basis, determine the volume variance.