Question 926430
While factory C produces {{{1000}}} computers,
{{{1000*0.049=49}}} probably defective,
factory A produces {{{2*1000=2000}}} computers,
{{{2000*0.033=66}}} probably defective, and
factory B produces {{{7*1000=7000}}} computers,
{{{7000*0.034=238}}} probably defective.
So during that period, the number of defective computers produced is expected to be
{{{49+66+238=353}}} ,
and of those {{{353}}} defective computers, {{{49}}} came from factory C.
So the probability that the randomly selected defective computer comes from factory C must be
{{{49/353=about0.1388}}} (rounded)
Maybe you would like to round it to {{{0.193=19.3%}}} ,
since the probability data given for each factory had only 2 significant digits.