Trouble Germinating

Whats the longest should it take to germinate using the same method.
I have currently 27 seeds I started 8 days ago.
10 were a strain called ICE
10 Hawian Skunk
1 Roadrunner
1 Moby Dick.
and 5 of an unknown strain.
8 of 10 of the Skunk are up the roadrunner is and 4 of 5 of the unknown are up.
None of the ICE has come up up at all nor did the Moby Dick.
I use a peat coco mix to germinate and have always had good luck.
Do certain strains take longer or do I have some duds.
I got them from the attitude.

I would personally give it 2 weeks. I've had some seeds from attitude that were duds too

are you keeping it moist? but i have seen beans take up to 18 days to germ, my super silver haze for example...lol

ive had problems before should not take longer than 2 weeks temp??

Are you keeping them in a warm dark place?

temp should be on the warmer side and medium should stay moist and no light is need until they pop. What i do is use promix in cups with holes in the bottom, dark closet, plastic wrap over the top to keep moister in, mine usually sprout within24-48 hours