Final answer:
Christine should purchase individual disability insurance coverage for $1,150 per month to cover her monthly expenses minus the employer's disability insurance coverage and work-related expenses.
Step-by-step explanation:
To determine how much individual disability insurance Christine should purchase, we start with her total monthly expenses of $1,800. Since $50 of these expenses are work-related, and her employer provides $600 of disability insurance coverage, we can calculate the shortfall that Christine needs to cover with individual insurance.
First, we subtract the employer-provided disability insurance coverage from the total monthly expenses:
$1,800 - $600 = $1,200.
Then we further subtract the work-related expenses since they would not be necessary if Christine is off work due to disability:
$1,200 - $50 = $1,150.
Therefore, Christine should consider purchasing individual disability insurance coverage for the remaining amount of $1,150 per month to cover her monthly expenses if she becomes disabled.