Answer:
100
Step-by-step explanation:
n(u)=120 total people in survey
n(c)=97 people carrying cell phone
n(t)=12 people carrying tablet
n(c∩t)=9 people carrying both tablet and cell phone
n(c∪t)=? people carrying cell phone or tablet
now,
n(c∪t)= n(c)+n(t) - n(c∩t)
= 97+12-9
=109-9
=100
there fore the number of people carrying cell phone or tablet = 100