Answer:
3
Step-by-step explanation:
6 have visited a zoo.
6 have visited a factory.
3 visited both.
Of the 6 who visited a zoo, 3 also visited a factory.
Of the 6 who visited a factory, 3 also visited a zoo.
Here is the list of students:
3 visited a zoo but not a factory.
3 visited a factory but not a zoo.
Answer: 3
43
18x+7
=18×2+7
=36×9
=45