memory upgrade

I new to the forums so apologise if I'm asking a question already been asked

I have a mid 2011 model imac 27" which currently has 4gb of ram can i buy a 4gb stick of ram and put it straight in to work along the 4gb i have or do i need to buy 2 4gb sticks and pair them up

thanks

G'day and welcome top the forums

There are four memory slots in your iMac. Easiest way is to buy 2 x 2GB or 2 x 4GB and pop them in. They will still be in matched pairs.

Memory up to 32GB for Apple iMac 2011 Thunderbolt equipped models