13. What can be concluded given the following statements, using the Law of Syllogism: If I eat candy late a night, I will get a stomach ache. If I get a stomach ache, I will not be able to sleep.

A. If I eat candy late at night, then I will not be able to sleep.

B. If I get a stomach ache, then I ate candy late at night.

C. If I am not able to sleep, then I ate candy late at night.

D. If I am not able to sleep, then I have a stomach ache.

14. Determine which conclusion can be drawn from the two statements: If three points lie in a plane, they are coplanar. Points A, B, and C lie in plane D.

A. Points A, B, and C are collinear.

B. Points A, B, and C are coplanar.

C. Points A, B, and C are noncollinear.

D. No conclusion can be reached.

17. Which of the following is a counter-example of the conjecture that all triangles are scalene?

A. an acute triangle

B. an isosceles triangle

C. an obtuse triangle

D. a right triangle