Question

Abel Alonzo, Director of Human Resources, is exploring employee absenteeism at the Plano Power Plant. Ten percent of all plant employees work in the finishing department; 20% of all plant employees are absent excessively; and 7% of all plant employees work in the finishing department and are absent excessively. A plant employee is selected randomly; F is the event "works in the finishing department;" and A is the event "is absent excessively." P(A ∪ F) = _____________.

(A) 0.07
(B) 0.10
(C) 0.20
(D) 0.13 (E) 0.17

Answer 1

Answer: 0.23

Explanation:

Given : F is the event "works in the finishing department;"

and A is the event "is absent excessively."

Given : 10% of all plant employees work in the finishing department; 20% of all plant employees are absent excessively; and 7% of all plant employees work in the finishing department and are absent excessively.

i.e. P(A)= 0.20 ; P(F)=0.10 ; P(A ∩ F) = 0.07

We know that
`P(X\cup Y)=P(X)+P(Y)-P(X\cap Y)`

Then,

`P(A\cup F)=P(A)+P(F)-P(A\cap F)\\\\\Rightarrow\ P(A\cup F)=0.20+0.10-0.07=0.23`

Hence, the required answer is
`P(A\cup F)=0.23`