Book of Riddles ✓

39

Answer 38 >> 43.
After 6 all the numbers divisible by 3 can be ordered (because they can all be expressed as a sum of 6's and 9's). After 26, all number divisible by 3 then subtracted by 20 can be obtained. After 46, all numbers divisible by 3 then subtracted by 40 can be obtained. After 46, all numbers fit into one of these 3 categories, so all numbers can be obtained. 43 is the last number that doesn't fall into one of these categories. (44= 20 + 6 x 4 , 45= 6 x 6 + 9)

Riddle 39 >>
My first is often at the front door.
My second is found in the cereal family. My third is what most people want.
My whole is one of the united states. What am I?