can u pls explain this

EXAMPLE 2.2 Consider the execution of a program that results in the execution of 2 million instructions on a 400-MHz processor. The program consists of four major types of instructions. The instruction mix and the CPI for each instruction type are given below, based on the result of a program trace experiment: The average CPI when the program is executed on a uniprocessor with the above trace results is CPI=0.6+(20.18)+(40.12)+(80.1)=2.24. The corresponding MIPS rate is (400106)/(2.24106)178