"twice per decade" = 2 / 10 years = 1nce per five years
The letter E
1 decade is 10 years, thus: 1 year =1/10 decade = 0.1 decade
10 years! (a decade)
A decade is 10 years
1 Decade= 10 years
The answer to the riddle is the letter "e." It appears once in the word "year" and twice in the word "decade."
The letter "e."
It depends on the decade. Sometimes once, sometimes twice.
The letter DDAYDECADECENTURY
The Letter "e"
The letter E
The letter E
e
M
The Letter "D"
The letter "e"
Letter e