Question 1196711
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Each urn is selected with probability {{{(1/3)}}} so we multiply that by the probability of selecting red from each urn, and add them:

{{{ (1/3)(4/11) + (1/3)(1/5) + (1/3)(3/8) }}}

which works out to  {{{ 907/1320 }}} or about 0.687  (68.7% chance to pick red)

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EDIT:  Oops, thanks tutor ikleyn.  To check my answer, I had calculated the probability of obtaining black (0.313) and accidently copied down that calculation.