Independent solution

How to solve this Probability Modeling question

Setup

Setup

Let the twin share be t. The king share is 3t, and the queen relation then also gives share t.

P(T)=t,P(K)=3tP(T)=t,\qquad P(K)=3t
P(Q)=P(K)+P(T)4=tP(Q)=\frac{P(K)+P(T)}4=t

Model

Model

Normalize the three mutually exclusive category shares t, 3t, and t to total one.

t+3t+t=1t+3t+t=1

Compute

Compute

Normalization gives t=0.2. King or queen sales therefore have combined share 3t+t=0.8.

t=0.2t=0.2
P(KQ)=3t+t=0.8P(K\cup Q)=3t+t=0.8

Answer

Answer

The required probability is 0.80, corresponding to choice C.

0.80(C)\boxed{0.80\quad\text{(C)}}