A local blood center needs donors and has advertised on the college campus. Faculty, staff, and students all donated during the drive. Many also volunteered to help set up, hand out materials, and clean up at the end of the event. There were a total of 500 people surveyed about their involvement that day. Two hundred fifteen of them gave blood. One hundred fifty-nine helped with setting up and cleaning up, as well as handing out materials. If eighty-seven people both helped and donated, how many people neither donated nor helped?

Question

anonymous · Answer

is it 39?

anonymous · Answer

There are 500 total people.  215 gave blood and 159 helped set up, giving a total of 374.  However, since 89 people did both, we counted those 89 people twice.  So we subtract 89 to get 285 total volunteers.  

500-285=215 did not volunteer