xmagedo wrote:

During a certain season, a team won 80% of its first 100 games and 50% of its remaining games. If the team won 70% 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

Thanks

This question can be orally solved using weighted averages (yet again!)

Of first 100 (w2) games, team won 80% (A2)

Of the remaining games, it won 50% (A1)

Overall the team won 70% (Aavg)

w1/w2 = (A2 – Aavg)/(Aavg – A1) = (80 - 70)/(70 - 50) = 1/2

Hence w1 = 50

Total number of games = 150

You can ofcourse use the scale method too.

If the formula and the term 'scale method' aren't making sense to you, check out:

http://www.veritasprep.com/blog/2011/03 ... -averages/
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