A bag contains 9 black marbles and 1 white marble.

What is the probability of the event that is complementary to the event of drawing a black marble from the bag?

Question

A bag contains 9 black marbles and 1 white marble. 

What is the probability of the event that is complementary to the event of drawing a black marble from the bag?

anonymous · Answer

@amistre64 @mathmale

amistre64 · Answer

the key here is in the terminology used ... how do you define a complementary even?

amistre64 · Answer

*event

amistre64 · Answer

a complementary event is an event that does NOT include the stated event.

If the stated event is pulling a black marble,  then the complementary event is pulling NOT a black marble.


How many NOT black marbles are there in this case?
How many marbles are there altogether?

anonymous · Answer

10 blacks marbles alltogether, 1 is not a black marble

amistre64 · Answer

then since the definition of probability is:

#success
--------
  #total

1/10 seems to be the probability of pulling NOT a black marble

amistre64 · Answer

if there had been say 1 white and 3 red ... then it should easily be seen that there would have been 4 NOT black marbles to determine :)  but they didnt give that scenario