Answer: $ 10.2
Step-by-step explanation:
Since, the old rate = $ 9.25 per hour,
⇒ The total earning in 12 hours with this rate ( Gross income ) = 12 × 9.25 = $ 111
Also, New rate = ( $ 5.90 + $ 4.20 ) per hour = $ 10.1 per hour,
⇒ The total earning with this rate ( gross income ) = 12 × 10.1 = $ 121.2
Thus, the total difference between the new income and old income = 121.12 - 111 = $ 10.2
⇒ New gross income is $ 10.2 dollars greater than the old gross income.