look at the chart- out of 150 dog owners 75 perfer human food only,45 perfer pet food only and 30 perfer both human and pet food.
So what percent of dog owners reported their dog likes either only human food or only pet food?
P(human food) = 75/150 = .5
P(pet food)= 45/150 = .3
or question so adding
.5 + .3 = .8
% = [part/total]*100.
human food only = [75/150]*100 = ??
pet food only = [45/150]*100 = ??
thanks for the help