Brain Teasers
Guess the Pattern 5
What is the next number in this series?
5, 9, 15, 21, 39, 45, 69, 81, 99, ?
5, 9, 15, 21, 39, 45, 69, 81, 99, ?
Answer
The series lists numbers that are two numbers away from two prime numbers.5 (3 and 7 are prime)
9 (7 and 11 are prime)
15 (13 and 17 are prime)
21 (19 and 23 are prime)
39 (37 and 41 are prime)
45 (43 and 47 are prime)
69 (67 and 71 are prime)
81 (79 and 83 are prime)
99 (97 and 101 are prime)
thus
105 (103 and 107 are prime)
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