Litecoin transaction status: 0/unconfirmed, Not in memory pool

[MikeA]

Hi 
This is a question about LTC Litecoin transaction status. i have sent coins to an exchange wallet to trade. Transaction is still showing pending.
Transaction fee is set at : 0.00189000 LTC.
The transaction status showing as:  0/unconfirmed, Not in memory pool.

Question 1: How long will it take for this transaction to be confirmed on LTC network?
Question 2: What does  0/unconfirmed, Not in memory pool mean?
Question 3: I have set the transaction fee at : 0.00189000 LTC, is this fee amount sufficient enough to get confirmed? If NOT then what do i need to set the fee amount to get the transaction cleared?

Your help is much appreciated
Thanks in Advance