I have categorize the questions for Form4 probability and Form 5 ones already!
Form4 got 4 types of questions
1st type: Find the possible outcome (inclusive of possible outcome of an event) This type of questions is asking students to write out sample space one.
Eg:
Throw a dice, a) list all possible outcomes b) list the possible outcomes if the outcome number is less than 4
a) {1, 2, 3, 4, 5, 6}
b) {1, 2, 3}
2nd type: Find probability
Eg: 2 girls out of 10 are fat. If a girl is randomly chosen, find the probability that the girl is fat
Answer: 2/10 = 1/5
3rd type: Find possible times the event occur
Eg: 2 girls out of 10 are fat. How many fat girls are there in 1500 girls?
Answer: 2/10 x 1500 = 300
4th type: Using unknown type
A box contains 5 yellow marbles, 3 green marbles and some blue marbles. A marble is chosen at random from the box. The probability of choosing a green marble is 1/4. Find the probability of choosing a blue marble.
Number of blue marbles = n
3/(5+3+n)=1/4
3/(8+n) = 1/4 then cross multiply
8+n = 3(4)
n = 12 - 8
n = 4
Probability of getting blue marble = 4/12 = 1/3
So these are the four types. First three type kacang nia. 4th type is hard for weak students cause' most of the time they dunno how to use unknown. But generally form4 one is kacang to us.
Form 5 one....Die lo. We dun prepare go in class oso can fish fish xia de...
Type 1: Double set without interfering each other
Eg: Two bags contain six balls each. Each bag has 3 red balls, 2 white balls and 1 blue ball. One ball is picked from each bag. Find th probability that both balls are blue.
So we just use 1/6 X 1/6 = 1/36
Type 2: Double set without replacement
This is the one I say dun prepare can die one. paling kek sui.
Eg: A group of 10 boys and 8 girls are assigned to write a report. First day, 2 people are chosen to write the report. Find the probability that both pupils chosen are girls.
So we need to use 8/18 x 7/17 = 56/306 = 28/153
Cause after one girl is chosen, left only 17 girl to choose.
Type 3: Set related (intersect = and, union = or, complement = not) This one only involve ONE set.
Eg: A group 40 boys (take note only 1 group) plays badminton and tennis. 25 play badminton and 29 play tennis. Each boy plays at least one of the games. How many boys play both badminton AND tennis?
In total got 25 + 24 = 49. But actually there are only 40 boys. So 9 ppl must play two games. Therefore probability = 9/40
Type 4: Kacang putih type. Similar to those in Form 4 one. Usually in the form of a table.
Eg:
Result Boys Girls
Pass 110 35
Fail 10 5
A pupil is chosen randomly. Find the probability that the pupil fails the test.
So just 15/160 = 3/32 can dy.
For Form4, next week no need introduce them to different questions. Only let them do (If got time) some random questions. The 1st week of holiday only we introduce types of questions to them
For Form5, next week we do revision of Form4 (Cause it is the 1st subtopic of their Form 5 chapter) Then we tell them Form4 got 4 types of questions. They must master all before proceeding to form5, or else they can die kaokao. So we basically revise, then let them do questions. So Form5 need to photostat something.
For Form5, you write the 4 category on the board. Then every question you do with them, ask them which is the category. And use which way to solve. So they can master form4 before proceeding la. Form 4 you want photostat question then go ahead ba. If not you just prepare some example, as you go thru you write the question on board and ask them solve lo. You suka la.
PS: I actually took two books home to study the question type. And the 2 books are actually our favourite book. xD So in case you need to use questions from the book, I scanning them. Will attach to our mailbox tonight. So you print the questions before photostating la. Paiseh xP
