Pg 327 (339) - Q25
Take your time with this problem. It says that you've got numbers R,S, and T, and that the average is twice the median. Well, they then tell you that R<S<T. Therefore, S has to be the median. So, you have the equation that (R+S+T)/3=2S. Well, they also tell you that R=0, so substitute zero in there for R. Then. they tell you that T=NS; so substitute NS for T. Thus, you're left with S+(NS/3)=2S, then you have S+N=6S; NS=5S. Therefore, N=5.