Question 1132889
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<pre>
(a)  {{{20/(140+100)}}} = {{{20/240}}} = {{{1/12}}}.    <U>ANSWER</U>


(b)  {{{((140-70) + (100-20))/(140+100)}}} = {{{150/240}}} = {{{5/8}}}.    <U>ANSWER</U>


(c)  {{{70/(140+100)}}} = {{{70/240}}} = {{{7/24}}}.    <U>ANSWER</U>
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All questions of this post and all solutions are TRIVIAL.


You simply need to know the basic definition of probability to solve them on your own.