A survey of members of a health club found that:
24 members swim;
32 members use exercise bikes;
20 members use weight machines;
8 members swim and use weight machines;
13 members use exercise bikes and weight machines;
12 members use exercise bikes only;
5 members swim, use exercise bikes, and use weight machines;
6 members do not swim and do not use either exercise bikes or weight machines
Use a Venn diagram to determine how many members were surveyed