Each of these numericalÂ groups conclude with the exact same number. Your mission, should you choose to accept it, is to identify the concluding number and explain why it's the same in each case.
17, 9, ?
1, 3, 5, ?
20, 6, 3, 5,Â ?
HERE is the answer.
In each case, the answer is FOUR.Â The next number in each sequence is the number of lettersÂ used toÂ spelling out the previous number.
SEVENTEEN (9 letters) -> NINE (4 letters) -> FOUR
ONE (3 letters) -> THREE... READ ON