Carol was sending out birthday invitations to 10 friends. If each package of invitations she bought had 2 invitations in it how many packs does she need so that no friend gets left out?
Carol is sending out birthday invitations to 10 friends. 

This means that she needs 10 invitations in total. 

Each package of invitations she bought has 2 invitations in it. 

This means that she needs 5 packages of invitations in total.