In this paper, we find upper bounds on the open packing and k-limited
packing numbers with emphasis on the cases k = 1 and k = 2. We solve
the problem of characterizing all connected graphs on n vertices with
ρo(G) = n/δ(G) which was raised in 2015 by Hamid and Saravanakumar.
Also, by establishing a relationship between the k-limited packing number
and double domination number we improve two upper bounds given by
Chellali and Haynes in 2005.