Task: Question Answering
Input (English): Problem: if x , y , and z are positive real numbers such that x + y - z = 100 , y - z + x = 120 , and z - x + y = 50 , then find the x + y + z value ? 
Options: a ) 100 , b ) 120 , c ) 150 , d ) 200 , e ) 160
Output (English): b