The question is the prepaid insurance account had a 6,000 debit balance at Dec.31, 2008 before adjusting for the costs of expired coverage. An analysis of the company's insurance policies showed that 1,100 of unexpired insurance coverage remains how do I prepare this as a djusting entry

Give it a try yourself and I will let you know how you did. Explain you calculations in the process please.

I think that youtook the 1,100 of the unsed coverage and subtracted 6,000 you had as a debit balance and that's how you came up with 4,900

So what would the JE be?

Debit Insurance Expense for the amount of insurance used
Credit Prepaid Insurance for the amount of insurance used.

In your problem to calculate the amount of insurance used you need to subtract the unexpired Insurance from the amount in Prepaid Insurance. This is the amount of insurance used.