PROBABILITY

Question 1

KEYWORD

“AND”

Answer 1

P(AnB)

Independent events

P(A) X P(B)

Question 2

KEYWORD

“OR”

Answer 2

P(AUB)

INDEPENDENT EVENT

P(A) + P(B)

Question 3

KEYWORD

“Given” or “if” or “conditional”

DEPENDENT EVENTS

Answer 3

P(AnB) = P(A/B) X P(B)

Or

P(A/B) = P(AnB) / P(B)

Question 4

Permutations

nPr = n! / (n-r)!

Answer 4

A number of distinct ways of arranging a subset(r) of objects drawn from a larger group(n) of objects.

DO THIS WHEN ORDER IS IMPORTANT

Question 5

Combinations

Answer 5

A number of district ways of arranging a subset of objects(r) drawn from a larger group of objects(n)

nCr = n! / r!(n-r)!

ORDER IS NOT IMPORTANT