Answer:
5
Step-by-step explanation:
If we call A the group that has a tablet computer and B the group that has a smartphone. In this case we can apply a formula that tells us that:
# (AUB) = #A + #B - #AnB - NoANoB
We know all these values except the one that has neither A nor B.
# (AUB) = the number of respondents, that is 117.
#A = The number of people who have a tablet, that is 81.
#B = The number of people who have a smarphone, that is, 70.
#AnB = intersection of both groups, that is, they have both, that is 29.
Replacing:
117 = 81 + 70 - 29 - NoANoB
NoANoB = 81 + 70 - 29 - 117
NoANoB = 5
Which means that 5 people have neither a tablet nor a smartphone.
