What is the null Hypothesis (Ho) And Alternative hypothesis(Ha)? If possible please in symbols?

The human requirement for salt is only 220 milligrams per day, which is surpassed in most single servings of ready to eat cereals. If a random sample of 20 similar servings of Special K has a mean sodium content of 244 milligrams of sodium and standard dev of 24.f milligrams, does this suggest at the .05 level of significance that the average sodium content for single servings of special K is greater than 220 milligrams?