Brain Teasers
Counting Up
What is the next number in this series?
1, 4, 7, 11, 15, 18, 21, 24, 27, ?
1, 4, 7, 11, 15, 18, 21, 24, 27, ?
Answer
73after 0, the first number with three letters is 1 (one)
after 1, the first number with four letters is 4 (four)
after 4, the first number with five letters is 7 (seven)
after 7, the first number with six letters is 11 (eleven)
after 11, the first number with seven letters is 15 (fifteen)
after 15, the first number with eight letters is 18 (eighteen)
after 18, the first number with nine letters is 21 (twenty-one)
after 21, the first number with ten letters is 24 (twenty-four)
after 24, the first number with eleven letters is 27 (twenty-seven)
thus
after 27, the first number with twelve letters is 73 (seventy-three)
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