Question

Can someone help me with this and explain please

Answer 1

X/y = 2 so x = 2y
z/x = 4 so z = 4x but x = 2y so z = 4(2y) = 8y

now you have
x = 2y, z = 8y 

x + y + z          2y  + y + 8y             11y              11
------------ = -----------------------= ------------- =   ----------- = 5 1/2
     x                          2y                  2y                  2

answer
C. 5 1/2