Find the next number is the sequence

1, 2, 6, 21, 4, 0, ?

The late fee for library books is $2.00 plus 15¢ each day for a book that is late. if maria’s fee for a late book was $3.20, write and solve a linear equation to find how many days late the book was.

What is the probability of rolling a single die greater than 4

According to the data set, where should the upper quartile line of the box plot be placed?