The Alphabet Number
I am a number. Spell me out in English and my letters are in perfect alphabetical order. What number am I?
40
Thinking time
No peeking until the ring closes.
It is less than 100.
40
F, O, R, T, Y: every letter comes later in the alphabet than the one before.
How to solve it
Write numbers out in English and check whether each letter comes later in the alphabet than the one before.
Small numbers fail fast. ONE breaks at once, because N comes before O in the alphabet. TWO breaks at the O, THREE at the H, and FOUR at the R, which comes before U.
FORTY works. F is letter 6, O is 15, R is 18, T is 20 and Y is 25, and 6 < 15 < 18 < 20 < 25.
The usual slip is FOUR, since it starts well with F, O, but R comes before U.
