Final answer:
To calculate the additional 0.9% HI tax on all total earnings, you multiply the total earnings by 0.9% (0.009).
Step-by-step explanation:
To calculate the additional 0.9% HI tax on all total earnings, you need to find the total earnings. The year-to-date earnings as of the 24th paycheck are $196,800, and the year-end bonus is $100,000. So the total earnings would be $196,800 + $100,000 = $296,800.
To calculate the additional 0.9% HI tax on the total earnings, you multiply the total earnings by 0.9% (0.009). So the additional HI tax would be $296,800 * 0.009 = $2,671.20.