memorise

Question 1

notation

Answer 1

Question 2

note

Answer 2

always take into account of probabibilites outside the box too !

Question 3

note : when in doubt use this two way table :

Answer 3

A A’

B

B’

Question 4

S/D (conditional) which one do you consider first before picking rows in the two way table ?

Answer 4

D ( the one on the right )

Question 5

IMPORTANT NOTE :

Answer 5

even if you are doing independent probabilites, in the A level syllabus they have to add to 1, thus you have to take away probabilities from whatever is in the middle bits of the venn diagram

Question 7

another important note

Answer 7

when calculating conditional probabilities, make sure to calculate them in probability form :

Question 9

IMPROTANT NOTE ABOUT PROBABILITIES

Answer 9

if venn diagram has probabilities, then use the A u B equation. if itsm ade of regular numbers, then simply add all the numbers in diagram up

Question 10

P ( B/A)

MEMORISE THIS FORMULA

(ALSO WORKS WITH… P (B/A’) OR ANY OF THAT SORT )

EG. .

Answer 10

P(B n A) / P (A)

Question 11

p ( A n B’ )

Answer 11

p(A) - P(A n B)

Question 13

IMPORTANT NOTE ABOUT THE OUTSIDE OF VENN DIAGRAMS ?

Answer 13

COUNT THEM IN YOUR CALCULATIONS

Question 15

memorise this way of drawing out + doing venn diagrams

Answer 15

https://www.youtube.com/watch?v=JzTLWX6W6Yc&list=PLIy0I0VLj3aiBiiKqyP1bSXjk18R5SAlX&index=10

NOTE: get the INTERSECTION probabilites FIRST !

Question 16

Go over this like 10 days before the exam

Answer 16

https://www.youtube.com/watch?v=EzYTgntOZsI&list=PLIy0I0VLj3aiBiiKqyP1bSXjk18R5SAlX&index=9

Question 17

note for venn diagram questiosn

Answer 17

IF THEY DONT ASK YOU TO DRAW A VENN DIAGRAM, IT IS LIKELY THAT THEY JUST WANT YO UTO USE A PROBABILITY EQUATION

EG. P (A n B ) = P(A) + P(B) - P (A U B )

Question 18

probability of “atleast 1 being sweet”

Answer 18

1 - p ( neither are sweet )

Question 19

what does uniform rod mean

Answer 19

Modelling the beam as uniform means that the centre of mass of the seesaw is at C, and so weight of the seesaw can be ignored when taking moments about C.

Question 20

Answer 20

Question 21

where should “x” be ????

Answer 21

draw THE GODAMN DIAGRAM CAREFULLY, “x” should be just “x” metres away from A

i did some useless shit where i did smth like “x-10” or some retarded shit like that smh

Question 22

50 * 80

Answer 22

4000

Question 23

Question 24

when a particle is tilting about a pivot (eg A)

Answer 24

the reaction at any other support or reaction at any other string is ZERO

Question 25

limiting equillibrium

Answer 25

f= uR

Question 26

uniform

Answer 26

Modelling the ladder as uniform allows us to assume the weight acts through the midpoint