Answer: 4.37%
Step-by-step explanation:
As interest is tax deductible, the Sundial Interest needs to be adjusted for tax to find out the true return.
Jackson as a single tax payer earning $47,500 in 2019 has a tax rate of 22% according to the IRS Tax bracket for that year.
That means that the interest that true interest that Sundial is offering him is,
= 5.6 * ( 1 - tax rate)
= 5.6 * ( 1 - 0.22)
= 5.6 * 0.78
= 0.04368
= 4.37%
To make Jackson indifferent with the same amount of risk, the city of Mitchell would have to offer him the same interest that Sundial is offering net of tax which is 4.37%.