| Date | May 2018 | Marks available | 3 | Reference code | 18M.1.sl.TZ2.2 |
| Level | SL only | Paper | 1 | Time zone | TZ2 |
| Command term | Write down | Question number | 2 | Adapted from | N/A |
Question
Consider the following propositions.
p : the baby cries
q : the baby is happy
r : the baby wants to play
Write down, in words, (q∧r)⇒¬p(q∧r)⇒¬p.
[3]
a.
Complete the following truth table.
[2]
b.
State whether (q∧r)⇒¬p(q∧r)⇒¬p is a tautology, contradiction or neither.
[1]
c.
Markscheme
if the baby is happy and wants to play then the baby does not cry (A1)(A1)(A1) (C3)
Note: Award (A1) for “If… then…”; (A1) for “the baby is happy and wants to play”, (A1) for “the baby does not cry”. Crying must be negated.
[3 marks]
a.
(A1)(A1) (C2)
Note: Award (A1) for each correct column.
[2 marks]
b.
Neither (A1)(ft) (C1)
Note: Follow through from the last column in their part (b).
[1 mark]
c.
Examiners report
[N/A]
a.
[N/A]
b.
[N/A]
c.
Syllabus sections
Topic 3 - Logic, sets and probability » 3.3 » Truth tables: concepts of logical contradiction and tautology.
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