BO LIAO stuff from 05S0929:
1) physics paper was ironic. we have options for non-option questions and no option for option questions.
2) if we improve technology, there's a shift in supply curve. Employment increases.
but when we improve technology, there's a shift in PPF out. Then employment rate decreases.
3) for mcq, lets take chem as an example. probability of getting a question right is 1/4. 1 mark awarded to right answer and zero marks deducted for wrong answer. Then expected mark for every question is 1/4. Since there are 40 questions, there are 40 random samples, then the expectation will be 10. So if we get above 10, we're above expectation!