He chooses his two cards and they are both multiplication cards. Is choosing two multiplication cards likely?
Let:
A = Draw an addition card
B = Draw a subtraction card
C = Draw a multiplication card
N = Total number of cards
[tex]\begin{gathered} P(A)=\frac{42}{100}=4.2 \\ P(B)=\frac{56}{100}=5.6 \\ P(C)=\frac{2}{100}=0.02 \\ P(C|C)=\frac{P(C\cap C)}{P(C)}=0.02 \end{gathered}[/tex]Choosing two multiplication cards is very unlikely, the probability of that is only 2%.
Part A:
There are many possibilities, for example:
Draw an addition card and draw a subtraction card:
[tex]P(B|A)=\frac{P(A\cap B)}{P(B)}[/tex]The possibles outcomes can be found using a permutation:
[tex]\begin{gathered} P(n,r)=nPr=\frac{n!}{(n-r)!} \\ P(3,2)=3P2=\frac{3!}{(3-2)!} \\ P(3,2)=6 \end{gathered}[/tex]The measured variables are:
P(A) = Probability of draw an addition card
P(B) = Probability of draw a subtraction card
P(C) = Probability of draw a multiplication card
P(A ∩ B) = Probability of draw an addition card and a subtraction card
P(B ∩ C) = Probability of draw a subtraction card and a multiplication card
P(A ∩ C) = Probability of draw an addition card and a multiplication card