the sum of seven consecutive integers is 980. How many of them are
prime?  Choices:
A) 0 B) 1 C) 2 D) 3 E) 4
The middle number is 140 and the seven numbers are 137, 138, 139, · · · , 143.   Now 138, 140, and 142 are even, 141 is divisible by 3, and 143 - by 11. The remaining   numbers 137 and 139 are prime (it is easy to check that they are not divisible by 2,3,5,7   and 11).   correct answer 2
<result>C</result>
the sum of seven consecutive integers is 980. How many of them are
prime?