statistic question i don't know what the answer is- please help
a consumer survey indicates that the average household spends an average of $155 on groceries each week. The distribution of spending amounts is approximately normal with a standard deviation of $25. Based on this distribution.
a- what proportion of the population spends more then $175 dollars per week on groceries?
b- what is the probability of randomly selecting a family that spends less than $100 per week on groceries?
c- how much money do you need yo spend on groceries watch week to be in the top 20% of the distribution?