Based on the fact that the non-taxable life insurance benefit is $400, the amount that Joseph would have to earn is $555.56.
This can be found as:
= Non-taxable benefit amount / (1 - tax bracket rate)
Solving gives:
= 400 / (1 - 28%)
= 400 / 0.72
= $555.56
Find out more on non-taxable benefits at https://brainly.com/question/1581158.
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