How to find the percentages of all samples for 3 men?, assignment help

According to the study brain wights of Swedish men are normally distributed with a mean of 1.40 kg and a standard deviation of 0.11 kg.A) Determine the percentage of all samples of 3 Swedish men that have mean brain weights within 0.1 kg of the population mean brain weight of 1.40 kg. Interpret your answer in terms of sampling error.B) Repeat part (a) for samples of size 12.Can you please help me solve this step by step?The solution=88.12% But how do you get this answer?Thanks!