Re: a few more general GRE math problems

["Peacenik"]

"Daniel Mayost" <mayost@xxxxxxxxx> wrote in message 
news:en84pa$stu$1@xxxxxxxxxxxxxxxxxxx
> In article <1167557963.377775.165150@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
> john <johnboy98105@xxxxxxxxx> wrote:
> > These ones either I got them wrong or guessed and got them right.
> >
> > Q1:
> >
> > Average (arithmetic mean) of Test Scores in Class R
> > Average scores for the boys 90
> > Average scores for the girls 81
> > Average scores for the class 84
> >
> > What is greater? The number of boys in the class who took the test  or
> > The number of girls in the class who took the test.
> >
> > A1: the number of girls took the test is greater.
> >
> > I got so confused on this... Some tips will be welcome
>
> Formally, if there are b boys and g girls in the class we have, by
> equating the total scores we get:
>
> 90 b + 81 g = 84 (b+g)
>
> 6b = 3g
>
> 2b = g
>
> There are thus twice as many girls as boys in the class.

Infomally, the average (84) is closer to 81 than to 90, so the girls' scores 
must have more weight. Therefore there are more girls in the class.