Help please

In the EA] sampling problem, the population mean is $51,200 and the population standard deviation is $5,000. When the sample size is n = 20, there is a 0.4085 probability of obtaining a sample mean within +/- $600 of the population mean. Use z-table. a. What is the probability that the sample mean is within $600 of the population mean if a sample of size 40 is used (to 4 decimals)? b. What is the probability that the sample mean is within $600 of the population mean if a sample of size 80 is used (to 4 decimals)