[Question]: To buy a book, you pay $20 for each of the first 5 books at the supermarket, and for each additional book you buy over $20, you receive a discount of $2. If Beatrice bought 20 books, how much did she pay at the supermarket?
[Answer]: For the first five books, the total cost is $20 * 5 = $100. For every additional book over $5, you pay $2 less, totaling to $20 - $2 = $18. Beatrice bought 20 books, so the number of books at which she received the $2 discount is 20 - 5 = 15 books. For the 15 books, Beatrice paid 15 * $18 = $270. In total, Beatrice paid $100 + $270 = $370 for the 20 books.
So the answer is 370.

[Question]: Vince owns a hair salon and he earns $18 per head. His monthly expenses are $280 for rent and electricity and 20% of his earnings are allocated for recreation and relaxation. He will save the rest. How much does he save if he serves 80 customers a month?
[Answer]: This month, Vince earns 80 x $18 = $1440. The amount he allocates for recreation and relaxation is 20 / 100 x $1440 = $288. Thus, his monthly expenses is $280 + $288 = $568. Therefore, he saves $1440 - $568 = $872.
So the answer is 872.

[Question]: The student council sells scented erasers in the morning before school starts to help raise money for school dances. The local bookstore donated 48 boxes of erasers. There are 24 erasers in each box. If the student council sells the erasers for $0.75 each, how much money will they make?
[Answer]:
There are 48 boxes x 24 erasers = 1,152 erasers. The student council will make 1,152 erasers x $0.75 = $864.
So the answer is 864.