a bag has 6 purple marbles

Question

a bag has 6 purple marbles, 5 yellow marbles, 8 clear marbles and 3 turquoise marbles if a marble is choose at random whats the odds its purple?

Answer 1

Be careful --  odds are not the same as probability !

PLZ refer to http://www.math-magic.com/probability/prob_to_odds.htm

The ODDS that a marble will be purple is:

                       # of desirable outcomes   :  # of undesirable outcomes

             Odds are   6 to 16  (or 3 to 8) that a purple marble will be drawn.

Answer 2

Hi Sheilu,

 

You state the problem asks for the odds of choosing purple not the probability.  Probability is the #of favorable outcomes/# total outcomes.

 

Odds are slightly different # of favorable outcomes : # of unfavorable outcomes

 

A favorable outcome in this case is picking purple which there are 6

 

Unfavorable outcomes happen when a marble that is not purple is picked (5 yellow, 8 clear, and 3 turquoise), 16 unfavorable outcomes.

 

So...

 

6:16   or reduced (divide each by 2) --> 3:8

 

I am available for online tutoring, feel free to contact me if you are interested.

Answer 3

While its true that the probability that a marble chosen at random will be purple is 3/11, the odds against it happening are 8:3 which is almost 3 to 1. The answer to the question depends on how it is worded. If you want the probability that a marble chiosen at random is purple then that is 6/22 because you divide the number of purple by the total number of marbles. If you want to know what the odds are then there are 16 outcomes that are not purple and only 6 that are, so it is 16 to 6 against it being purple. In both cases these ratios can be reduced to 3/11 and 8 to 3 respectively.

 

Answer 4

Just to add on to Susan, to find probability in general, it is:

 

Total POSITIVE outcome

Total Possible outcomes

 

so since 6 outcomes result in a positive result (getting a purple), and there are 22 total outcomes (22 marbles), it's

 

 6

22

Answer 5

Hi Shellu,

The prob that random marble is purple = (# purple marbles) / (total # marbles)
= (6) / (6+5+8+3)
= 6 / 22
= 3 / 11 (reduced - the answer)

If you need additional help, please feel free to contact me regarding setting up an online tutoring session.

Thanks!

Susan