## Here are some solutions to the exercises I have given.

### First Exercise

#### Exercise 10-1

5. Albino crows are known to exist.
Translated as: All albino crows are those known to exist. Type A.

7. There are plenty of immodest failures.
Some failures are immodest. Type I.

16. Omnivores usually are not vegetarians.
Some omnivores are not vegetarians. Type O.

#### Exercise 10-3

(4)1. No professors are poor lecturers. (If true)

2. All poor lecturers are nonprofessors. --> True

3. Some professors are not poor lecturers. --> True (because professors exist.)

4. Some poor lecturers are professors. --> False

5. Some poor lecturers are nonprofessors. --> True (because there are poor lecturers)

#### Exercise 10-5

1. Some scientists are impractical.
Type I.

9. All professors who forget useless trivia are failures on TV quiz shows.
Type A.

### Second Exercise

#### Syllogism

4. Not all students wear uniforms to school.
Therefore, some BBA students are disrespectful of the authorities,
because any student who does not wear uniform to school is disrespectful of the authorities.

"Not all students wear uniforms to school" is translated as "Some students do not wear uniforms to school.

So the syllogism becomes

Some students do not wear uniforms to school.
All students who don't wear uniforms to school are disrespectful of the authorities.
Therefore, some BBA students are disrespectful of the authorities.

As it stands we have to say that this is not a syllogism, because there are more than three terms. But if we change the first sentence a bit, the syllogism becomes

Some BBA students do not wear uniforms to school.
All students who don't wear uniforms to school are disrespectful of the authorities.
Therefore, some BBA students are disrespectful of the authorities.

The diagram is as follows:

According to the diagram, the argument is valid. (Can you see why?)

6. Genetically modified food is not dangerous.
This is so because humans have consumed it for a long time,
and anything that humans have consumed for a long time is not dangerous.

The syllogism becomes:

Food that humans have consumed for a long time is not dangerous food.
Genetically modified food is food that humans have consumed for a long time.
Therefore, no genetically modified food is dangerous food.

This argument is VALID. (Write your own diagram.)