[Question]: A class has 60 students. The number of students who bring their lunch is thrice the number of those who eat in the school cafeteria. The rest of the students don't eat lunch. If 10 students eat in the school cafeteria, how many don't eat lunch?
[Answer]: Multiplying the number of students eating at the cafeteria by three means that 3 * 10 = 30 students bring lunch. The total number of students that eat lunch is 10 + 30 = 40 students. Since the class has 60 students, those who don't eat lunch are 60 - 40 = 20 students.
So the answer is 20.

[Question]: Bryan's score on a math exam is 20. Jen scored 10 more than Bryan while Sammy scored 2 fewer than Jen. If the math exam has 35 points in all, how many mistakes did Sammy make?
[Answer]: Jen scored 20 + 10 = 30 on the exam. Sammy scored two less, so his score was30 - 2 = 28. Thus, Sammy made 35 - 28 = 7 mistakes.
So the answer is 7.

[Question]: Walter wants to serve hushpuppies to his guests for his annual fish fry event. He thinks each guest will eat 5 hushpuppies and he is having 20 guests. He can cook 10 hushpuppies in 8 minutes. How long will it take to cook all of the hushpuppies?
[Answer]:
He wants to serve 5 hushpuppies to each guest and he is having 20 guests so that's 5 * 20 = 100 hush puppies. He can only cook 10 hushpuppies at a time and he needs to cook 100 hushpuppies so that's 100 / 10 = 10 batches of hushpuppies. Each batch takes 8 minutes to cook and he has 10 batches to cook so it will take him 8 * 10 = 80 minutes.
So the answer is 80.