4.2z + 3.8z simplify the expression (Use the operation symbols in the math palette as needed. Simplify your answer. Use whole numbers or decimals for any numbers in the expression.)

The mean finish time was 185.52 with a standard deviation of 0.327 minute. the winning car driven by chris finished in 185.13. the previous year race had a mean finish time of 110.3 with a standard deviation of 0.106. the winning car that year driven by karen finished in 110.13 minutes. find their respective z-scores. chris - z-score karen “- z-score