Question 1181088
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<pre>

Use the basic formula of Elementary Probability theory


    P(A U B) = P(A) + P(B) - P(A∩B).


Substitute the given values into the formula. You will get


    {{{191/400}}} = {{{7/20}}} + P(B) - {{{49/400}}}.


It implies


    P(B) = {{{191/400 - 7/20 + 49/400}}} = {{{191/400 - 140/400 + 49/400}}} = {{{100/400}}} = {{{1/4}}} = 0.25.    <U>ANSWER</U>
</pre>

Solved, answered and carefully explained.


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