A clerk was asked to change a $10 bill. She returned 9 more dimes than nickels and twenty-one more quarters than dimes. How many coins of each did she return? This is kind of hard and I need a bit of help.

:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?

Ariel is working at a meat packing plant for 5 nights a week. her regular wage is $11 an hour. she earns tine and a half for any overtime hours. this week she worked 9 hours of over time .how much will ariel earn for overtime this week ?

Astudy was interested in determining if eating milk chocolate lowered someone's cholesterol levels.ten people's cholesterol was measured. then, each of these individuals were told to eat 100g of milk chocolate every day and to eat as they normally did. after two weeks, their cholesterol levels were measured again. is there evidence to support that their cholesterol levels went down? how should we write the alternative hypothesis? (mud = the population mean difference= before - after)a. ha: mud = 0b. ha: mud > 0c. ha: mud < 0d. ha: mud does not equal 0