Question 162537
Let A and B be independent events with P(A) = 1/4 and P(B) = 1/5. Find P(A <font face = "symbol">Ç</font> B) and P(A<font face = "symbol">È</font>B).

<pre><font size = 4 color = "indigo"><b>

For independent events only (Two events are independent if it were true
that one on them were known to be certain, likely, unlikely, or impossible,
that knowledge would not affect the probability of the other at all.)

P(A <font face = "symbol">Ç</font> B) = P(A)*P(B) = {{{1/4}}}*{{{1/5}}} = {{{1/20}}}

For any two events, whether independent or not,

P(A <font face = "symbol">È</font> B) = P(A) + P(B) - P(A <font face = "symbol">Ç</font> B)

P(A <font face = "symbol">È</font> B) = {{{1/4+1/5-1/20=5/20+4/20-1/20=8/20=4/5}}}

Edwin</pre>