Question 1190982
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There are  9x  yellow umbrellas,  10x  blue umbrellas and  11x  black umbrellas,

or   9x+10+11x = 30x,  in total.



The probability of getting a yellow umbrella is  &nbsp;&nbsp;{{{(9x)/(30x)}}} = {{{3/10}}} = 0.3 = 30%.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<U>ANSWER</U>