=In a certain business, all 300 employees use the phone or email. 155 use the phone, 175 use email, how many use both the phone and email?
155 use the phone, 175 use email,
if you add the two groups
155+175 = 330
since the business only has 300 employees not 330, we can assume that 30 people from each group are the same person
30 employees use both
125 use phone onlt
145 use email only
30+125+145=300 total employees