12:21 is the correct answer
The designer could use the measurements in pixels.
mbly code to implement the y=(x1+x2)*(x3+x4) expression on 2-address machine, and then display the value of y on the screen. Assume that the values of the variables are known. Hence, do not worry about their values in your code.
The assembly instructions that are available in this machine are the following:
Load b, a Load the value of a to b
Add b, a Add the value of a to the value of b and pla