$12.$ a$.$ Assume our model requires $1014$ computations to simulate one hour of activity. We run the program on a desktop computer with a computation speed of $800$ MIPS. How long will it take to simulate one day of activity in the model?

b$.$ How fast a computer $($in terms of MIPS$)$ do we need to use if we want to complete the simulation of one day in five minutes of computing time?