If x,y ,and z are positive real numbers such that x+y-z =50 , y-z+x =60 , and z-x+y = 80, then find the z value? Choose the most appropriate option:
A) 10	B) 20	C) 5	D) 15	E) 25
x+y-z =50, ------1)   y-z+x =60 , ------2)   z-x+y = 80------3)   from (1)&amp;(2)   2z=10   z=5   correct option is 5
<result>C</result>
If x,y ,and z are positive real numbers such that x+y-z =50 , y-z+x =60 , and z-x+y = 80, then find the z value?