I have seen lots of matches in which the D/L method was used to decide victory, but I never found out how it actually works. I know there are two keys in this method: overs and wickets in hand. Can anyone please explain it? And why does it not apply in test matches?
The Duckworth-Lewis method is explained on the ICC website:
Despite much confusion amongst the media, the players, and the public, the actual principle is relatively simple. When an interruption causes one team to have less resources available than the other team, the target is proportionally adjusted in the ratio of the resources available to each team.
For instance, if an interruption reduces the resources of the side batting second (Team 2) by 50% in comparison to Team 1's resources, the target would be reduced by 50%.
As you correctly mentioned, resources are composed of both wickets and overs. The D/L method does not add or subtract wickets or overs; it simply calculates what the target should be, given those resources.
While the principle is simple, it raises plenty of questions for discussion. I would strongly recommend reading the FAQ linked above, as they clarify many common queries.
Test Matches do not use the Duckworth-Lewis method because the number of overs per innings is not defined in a Test Match. Furthermore, a draw is a perfectly acceptable result in a Test Match.
If any interruption occurs by rain or audience duckworth luis method is applied to the team that takes batting in second innings of that match.It works on reducing overs limit. For example if team A makes170 runs for two wicketsafter 33.2 overs and match gets disturbed by rain,then the number of overs will be reduced to42 overs from 50.Number of overs to reduce depends on resources available i,e overs and wickets.probability works here asuming tht if team A plays 50 overs it might have done 296 runs in 42 0vers where the match overs limit was made.soteam B has to do297 runs in 42 overs to win the match . If team B can't win, it is not completely due to duckworth law as before beginning of 2nd innings itself a sheet will be given to captain stating at what runs will win the match if match stops at what over