Problema Solution
During the holidays, 24 people attended a holiday event. 13 of the attendees ate a piece of cake and 9 of the attendees ate a piece of pie. 16 of the attendees ate a piece of cake or a piece of pie (or both).
How many of the attendees ate both a piece of cake and a piece of pie?
Answer provided by our tutors
let n(cNp) denotes who ate both cake and pie
n(c) denotes who ate cake
n(p) denotes who ate pie
n(cUp)=n(c) +n(p)-n(cNp)
since we are calculating n(cNp) twice therefore we subtract it once
16=13+9 -n(cNp)
n(cNp) =22-16
=6