Question

x+y+z=9
w+y+z=5
w+x=2
What is the average of w, x, y, and z above?

Answer 1

x+y+z=9......(i)
w+y+z=5......(ii)
w+x=2......(iii)
from (iii) x = 2-w substituting in (i)
2-w+y+z =9 ;
y+z-w =7....(iv)
add (ii) and (iv)
(w+y+z)+( y+z-w) =7+5 = 12
w-w +y+y+z+z = 12
2y+2z =12
y+z =6 ....(v)
now add (iii) and (v) together
(w+x) +(y+z) =6+2 = 8
w+x+y+z =8.....(vi)
now from (vi) you can get the average which is simply 8/4 = 2