Question 254151: In a group of 40 students, 20 have cats, 15 have dogs, and 4 have both cats and dogs.
(a) How many students have neither cats nor dogs?
(b) How many students have cats but not dogs?
Found 2 solutions by dabanfield, solver91311:
Answer by dabanfield(803)   (Show Source):
You can put this solution on YOUR website! In a group of 40 students, 20 have cats, 15 have dogs, and 4 have both cats and dogs.
(a) How many students have neither cats nor dogs?
(b) How many students have cats but not dogs?
Of the 20 people who have cats, 4 also have dogs so 20-4 = 16 have cats only. Similarly 15-4 = 11 have dogs only. So we have:
16 cats only
11 dogs only
4 both dogs and cats.
The remaining students, 40-(16+11+4) = 9, have neither dogs nor cats.
Answer by solver91311(24713)  (Show Source):
You can put this solution on YOUR website!
If 4 have both cats and dogs and 20 have cats, then 16 must have a cat but not a dog. Similarly, if 4 have both and 15 have dogs, then 11 must have dogs but no cats.
So 16 plus 4 plus 11 equals 31 of the 40 students have one or the other or both leaving 9 that have neither.
John
|
|
|
