The probability of a Probability question appearing in your exams is probably 1, so Miss Loi probably thinks that it’s probably a good idea to finally include a probability problem here. (Try saying this in 5 seconds!)
Anyway, students should be alert to the fact that probability questions tend to be a little long-winded, low on mathematical figures/notations but high on rhetorics.
Sometimes you feel like you’re doing English comprehension right in the middle of your Maths paper, like this:
Lure by the promises of exotic virgins, endless rivers of wine, treasures of gold, meeting the Venerable Miss Loi and attaining Mathematical salvation, a gallant knight named John one day decides to embark on a quest to discover the whereabouts of Miss Loi’s Temple once and for all.
As such, this brave knight shall journey once a week (in shining armour and all) into the deep recesses of Novena, and brave the dangers that lurk within, till he finds the elusive Temple.
The probability of Sir John finding Miss Loi’s Temple in each journey to Novena is 1/5.
- Expressing your answers as fractions, find the probability that Sir John
- fails to find it in the first journey but finds it in the second journey.
- finds it either in the first or second week.
- fails to find it in the first three journeys.
- finds it in one of the first five weeks.
- Find the probability, in terms of n, that Sir John finds the Temple in one of the first n weeks.
Frankly this question is not difficult but a curious number of students contrive to get it wrong. The real danger here is probably that big mess of words designed to confuse the knight out of you. So read carefully.
What will John do when he finds the Temple eventually? Will he still make another journey the following week?