Solving Maths Problems: Numbers, Symmetries & Groups

[Firepanda]

http://img180.imageshack.us/img180/9589/simplell9.jpg

Is 1. c) as simple as i think it is?

I have gone through my notes and can't find anything to do with it, the module for it is Numbers, symmetries and groups, any ideas or do i simple just wack in 13/7 on my calculator and write down the answer?

Also, 1. d) I don't have a method of working that out.

I tried this though:

24/10 + (1)SIGMA(n) 39/(10^2n+1) = 2.43939393939...

But I don't know how to get this into a fraction from here.

 

[Rainbow Child]

For (d) the trick is to use the fact that 393939... repeats itself. Let a=2.4\overline{39} and compute 10a,\,1000a and subtract them.

 

[Firepanda]

a = 161/66 ;) thanks!

So i just assume 1.c) is a question made for a 10 year old?

 

[Rainbow Child]

Or for a nine and a half!

 

[belliott4488]

Actually, Firepanda, I think I could have solved all of these problems when I was ten ... or maybe a year or two later, I don't recall exactly. In what class did you run into these? I hope it wasn't "Calculus and Beyond"!

 

[Firepanda]

Well I'm 3 weeks into my Numbers, Symmetries and Groups module for 1st year university maths :P These are also assesed questions, so I can't complain :)

 

[belliott4488]

Ah ... so maybe they're just making sure that you've got your basics tucked under your belt?