Final answer:
The percent increase in salary for a worker who trains to become a teacher, going from $28,000 to $55,000, is 96.4%.
Step-by-step explanation:
To calculate the percent increase in salary for a worker who trains to be a teacher, we first determine the absolute increase in salary and then find the percentage that this increase represents of the original salary.
In this case, the worker's original salary is $28,000, and after training to be a teacher, the expected salary is $55,000.
The change in salary is: $55,000 - $28,000 = $27,000.
Now, we calculate the percentage change using the formula: Percentage change = (Change in quantity / Original quantity) × 100%.
Thus, the percentage increase in salary is: ($27,000 / $28,000) × 100% = 0.9643 × 100% = 96.43%, which can be rounded to the nearest 0.1% as 96.4%.