Sunday Express Mensa Teaser

[vivfrost]

Can somebody please explain to me the easiest way of working out one of these, where the columns equal certain numbers?

[prstanway]

Hi, The answer assuming I'm looking at the right mensa question is to put the information into equations like this:-
1. 2x+2y=58
2.c+2z+y=69
3.3y+z=71
then using simutaneous equations you substitute
from 1. above y=29-x making y the subject
now using 3.

3(29-x)+z=71 giving z=-16+3x
now using 2. x+2(-16+3x)+(29-x)=69
you get x=12

now you can get z and y using the same process

[prstanway]

Hi Viv
I do so hope this is the right puzzle.
An easier way to understand this is to again put the equations as :-
1. 2x+2y=58
2.x+2z+y=69
3.3y+z=71

Multiply equation 2 by 2:-
2. 2x+4z+2y=138
now deduct equation 1 from it which eliminates2x and 2y and leaves 4z=80 or z=20

just swap 20 for z in 3 giving y=17 etc.

[vivfrost]

Thanks so much for your help, it was the right puzzle.