Answer:
$1000
Explanation:
Given that :
Earning per month = $1000
Number of summer months = 3
Gross earning could be explained as an individual's total earning before making any deductions. Hence, for an individual who earn a monthly salary of $1000, and as not been subjected to any deduction such as tax, then the $1000 earning is the individual's gross earning.
From this explanation, we could conclude that Tina's $1000 monthly salary is her gross monthly income sincveit has not been subjected to any deduction and Tina has no other source of income.