Set A consists of the integers from 4 to 16, inclusive, while set B consists of the integers from 6 to 20, inclusive. How many distinct integers do belong to the both sets at the same time?  Choose the most appropriate option:  A) 5  B) 7  C) 8  D) 9  E) 11
A={4,5,6,7,8,9,10,11,12,...16}   B={6,7,8,9,10,11,12...}   Thus we see that there are 11 distinct integers that are common to both. 11 is the correct answer.
<result>E</result>
Set A consists of the integers from 4 to 16, inclusive, while set B consists of the integers from 6 to 20, inclusive. How many distinct integers do belong to the both sets at the same time?