How to plot cost curve with conditions

I want to calculate total cost graphically and created the following script. I got result for y = 0 10 20 30 40 50 30 35 40 45 50, however my desired result is y = 0 10 20 30 40 50 55 60 65 70 75.

Kindly help me in my desired results. I do not know what I am missing.

x=0:1:10;

z1 = (x<=5).*x;

z2 = (x>5).*x;

y = 10*z1 + 5*z2

plot(x,y)

Answer 1

[Andrei Bobrov]

y = cumsum((x <= 5 & x > 0)*10 + (x > 5)*5)

[Muhammad Asad Hanif]

Thank you so much mate, It works perfectly