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A team of medical students doing their internship have to assist during surgeries at a city hospital.The probabilities of surgeries rated as very complex,complex,routine,simple or very simple are respectively 0.15,0.20,0.31,0.26,0.08.Find the probabilities that a particular surgery will be rated routine or simple

$\begin{array}{1 1}(A)\;0.67\\(B)\;0.57\\(C)\;0.87\\(D)\;\text{None of these}\end{array} $

1 Answer

Toolbox:
  • $P(A \cup B)=P(A)+P(B)-P(A \cap B)$
Step 1:
Let us denote the surgeries very complex -A,complex -B,routine-C,simple -D,very simple -E
$P(A)=0.15$
$P(B)=0.20$
$P(C)=0.31$
$P(D)=0.26$
$P(E)=0.08$
Where by A,B,C,D & E are mutually exclusive to each other.
Step 2:
$P(C \cup D)=P(C)+P(D)-P(C \cap D)$
$\Rightarrow P(C)+P(D)$
$P(C \cap D)=\phi$
$\Rightarrow 0.31+0.26$
$\Rightarrow 0.57$
Hence (B) is the correct answer.
answered Jul 7, 2014 by sreemathi.v
 

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