When making a statistical inference about the mean of a normally distributed population based on a sample drawn from that population, wich of the following statements is correct, all else being equal?

Zelma buys p pounds of bananas for 40 cents per pound. she pays the clerk with a twenty-dollar bill. the clerk subtracts the total cost of the bananas from the twenty-dollar bill to determine the amount of change to give zelma. which expression represents the amount of change zelma should receive?