beginning of content:
SAT Subject Test
The numbers ,
, and
are three consecutive odd numbers that are prime. How many other triplets of consecutive odd numbers greater than
consist entirely of primes?
Select an Answer
None
Correct Answer:
Yes
One
Correct Answer:
No
Two
Correct Answer:
No
Three
Correct Answer:
No
More than three
Correct Answer:
No
View Correct Answer
You can look at some triplets of consecutive odd numbers greater than :
5, 7, 9
11, 13, 15
25, 27, 29
53, 55, 57
93, 95, 97
You should quickly observe that any triplet of consecutive odd numbers would have one multiple of . (The numbers that are multiples of
are bolded and underlined.) Therefore, the only triplet of consecutive odd numbers greater than 1 that contains all primes is
,
,
. The correct answer is (A).
Question Difficulty:
hard