56*55*54*53*52*51 = answer, or 56P6 if you know nPr notation and meaning.
ii. There are only 14 with no blue, therefore same method as i. except now we only have a total of 14 to choose from. Do you understand how to do this one?
iii. Same method as i. and ii. except the total now is 56 - 14 = 42. 42 tiles have a blue line, since 14 out of 56 don't. So no our total is 42, so how many ways to choose 6 from 42? Follow the same method I outlined in i. except in i. the total we started with was 56.