SOA Exam P Practice Q21

A survey of a group’s reading habits over the last year revealed the following information:
27% read horror novels
31% read mystery novels
26% read science fiction novels
12% read both horror and mystery novels
15% read both mystery and science fiction novels
10% read both horror and science fiction novels
6% read all three genres
Calculate the percentage of the group that read none of the three genres during the last year.
[A similar question can be found in the official SOA website: www.soa.org]