| Date | May 2013 | Marks available | 3 | Reference code | 13M.1.sl.TZ1.3 |
| Level | SL only | Paper | 1 | Time zone | TZ1 |
| Command term | Write down | Question number | 3 | Adapted from | N/A |
Question
Consider the following logic propositions:
p : Yuiko is studying French.
q : Yuiko is studying Chinese.
Write down the following compound propositions in symbolic form.
(i) Yuiko is studying French but not Chinese.
(ii) Yuiko is studying French or Chinese, but not both.
Write down in words the inverse of the following compound proposition.
If Yuiko is studying Chinese, then she is not studying French.
Markscheme
(i) \(p \wedge \neg q\) (A1)(A1)
Note: Award (A1) for conjunction, (A1) for negation of q.
(ii) \(p\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{ \vee } q\) OR \((p \vee q)\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{ \vee } (p \wedge q)\) (A1) (C3)
If Yuiko is not studying Chinese, (then) she is studying French. (A1)(A1)(A1) (C3)
Notes: Award (A1) for “if … (then)” seen, award (A1) for “not studying Chinese” seen, (A1) for correct propositions in correct order.
Examiners report
Some candidates found the phrase “Yuiko is studying French but not Chinese” confusing as they did not realize in this context the word “but” means “and”. Alternative but correct logic notation was accepted.
