Before play-offs, a certain team had won 80 percent of its games. Afte

The team played certain number of games before play-offs plus certain number of games in play-offs. We want to know what percent of all its games had the team won.

(2) says that the team won all of its play-off games.

Check complete solution here: https://gmatclub.com/forum/before-play- ... l#p1071527

Hope it helps.

Before play-offs, a certain team had won 80 percent of its games. After play-offs, what percent of all its games had the team won?
Let no. of games before playoff = x
Game wons = 80% of x = 0.8x

(1) The team competed in 4 play-off games.
so total no. of games = x+4. But here we don't know how many games team won. So we cannot calculate % of won games. So Not sufficient

(2) The team won all of its play-off games.
Team won all games. But we don't know how many games are being played. SO we don't know final total number of games. Not sufficient

1+2
Now we know team played 4 more games and won all
So total number of games = x+4
Total games won = 0.8x+4

% of games won = (0.8x +4) /(x+4) *100

Here we cannot solve equation as we don't know x and nothing cancels out. So Not sufficient.

Answer: E

Thanks a lot for the clarification Bunuel - please accept my Kudos also.

Given: Before play-offs, a certain team had won 80 percent of its games

Target question: After play-offs, what percent of all its games had the team won?

Strategy: It's sometimes useful to ask ourselves why the target question is impossible to answer without any additional information.
In this case, we can't answer the target question because we don't know the total number of games played before the playoffs, and we don't know the total number of games played during the playoffs.
When I scan the two statements, I see that neither of them provide information about the total number of games played before the playoffs.
This leads me to believe that the statements combined are still not sufficient.
So, I’m going to head straight to……

Statements 1 and 2 combined
There are several scenarios that satisfy BOTH statements. Here are two:
Case a: The team played 5 games before the playoffs, which means they won 4 of those 5 games (i.e., 80%). Then the team won all 4 of its playoff games. In total, the team played 9 games and won 8 of them. So, the answer to the target question is the team won about 89% of its games

Case b: The team played 20 games before the playoffs, which means they won 16 of those 20 games (i.e., 80%). Then the team won all 4 of its playoff games. In total, the team played 24 games and won 20 of them. So, the answer to the target question is the team won about 83% of its games

Since we can’t answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer: E

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