Answer:
Currently (assuming a 2020 tax schedule), Jorge and Anita's tax liability = $9,235 + [22% x ($146,500 - $80,250)] = $23,810
municipal bonds are not taxed by the federal government, so they do not pay any taxes on the interests earned on the City of Heflin bonds.
if they earn an additional $109,000, then their tax liability will be:
$29,211 + [24% x ($255,500 - $171,050)] = $49,479
their marginal tax rate = 24%