Re: South Africa V Ireland
Cricinfo answers you: 
You’ve been asking why D/L adjusts the target. Well, Ireland’s innings was interrupted (and not just once, but twice). So, they thought they had 50 overs originally and batted accordingly. Given that in the end they only had 35 overs, the target is adjusted upwards - the theory being that if they had known from the start they had 35, they would have hit out earlier. Wickets are a factor, too - the more you lose, the lower the revised target is. It makes sense if you think about it
