gmatprep 4

[resilient]

During a certain season, a team won 80 percent of first 100 games and 50 percent of its remaingin games. If the team won 70 percent of its games for the entire season, what was the total number of games that the team played?

a.180
b.170
c.156
d.150
e.105

qa is D, but cant seem to backsolve the answer and force choice d as the answer. I must be missing a small detail.

[amitansu]

Some books say while back solving/plugging start with choice D and E.
Largely one of them seem to correct answer !! (survey says)

So start with D here...

0.7 of 150 = 105
Now 80% first 100 games is 80 games; and 50% of remaining 50 games is 25.Now together they make 105 games.

[AleksandrM]

You could also use simple algebra:

80 +.5n/100 + n = 70/100, because the first part represents 70 percent of the total (100 + n) which is 100 percent of the games played.

Cross multiply to get:

70n + 7000 = 8000 + 50n

n = 50

100 + 50 = 150 total games played.

Also, just an aside, this is a Problem Solving question, and you should post it in the problem solving section instead of the Data Sufficiency section of the forum.