There is a crazy mailman who does not like to put more than $\mathbf{x}$ letters in a mailbox. If there are $\mathbf{b}$ mailboxes and $\mathbf{L}$ letters, is it possible for him to put all the letters in the boxes without exceeding $\mathbf{x}$ letters in any box?
- $x = 1, b = 10, L = 5$
- $x=1, b = 10, L = 20$
- $x=3, b=20, L = 50$
- $x = ?, b=90, L = 210$ (what is the smallest value of $x$ for which the mailman will be happy?)