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Date November 2010 Marks available 2 Reference code 10N.1.sl.TZ0.2
Level SL only Paper 1 Time zone TZ0
Command term Complete Question number 2 Adapted from N/A

Question

Complete the following truth table.

[2]
a.

Consider the propositions

     p: Cristina understands logic

     q: Cristina will do well on the logic test.

Write down the following compound proposition in symbolic form.

“If Cristina understands logic then she will do well on the logic test”

[2]
b.

Write down in words the contrapositive of the proposition given in part (b).

[2]
c.

Markscheme

     (A1)(A1)     (C2)

 

Note: Award (A1) for ¬q , (A1) for last column.

 

[2 marks]

a.

\(p \Rightarrow q\)     (A1)(A1)     (C2)


Note: Award (A1) for \(\Rightarrow\) , (A1) for p and q in the correct order.

 

[2 marks]

b.

If Cristina does not do well on the logic test then she does not understand logic.     (A1)(A1)    (C2)


Note: Award (A1) for If…(then), must be an implication, (A1) for the correct propositions in the correct order.

 

[2 marks]

c.

Examiners report

This question was well answered with most candidates able to complete the truth table correctly in part a) and write the correct compound proposition in symbolic form in part b). A significant number of candidates could not write the correct contrapositive, although most were awarded one mark for writing an implication.

a.

This question was well answered with most candidates able to complete the truth table correctly in part a) and write the correct compound proposition in symbolic form in part b). A significant number of candidates could not write the correct contrapositive, although most were awarded one mark for writing an implication.

b.

This question was well answered with most candidates able to complete the truth table correctly in part a) and write the correct compound proposition in symbolic form in part b). A significant number of candidates could not write the correct contrapositive, although most were awarded one mark for writing an implication.

c.

Syllabus sections

Topic 3 - Logic, sets and probability » 3.3 » Truth tables: concepts of logical contradiction and tautology.
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