Respuesta :

Melody08

Answer:

18

Step-by-step explanation:

Sum of x, y and z = 20 × 3

                             = 60

x-5+y+4+z-5 = 60-5+4-5

                    = 54

Mean of x-5, y+4 and z-5

= 54 ÷ 3

= 18