Question

An urn contains six red balls, five black balls, and four green balls. If two balls are selected at random without replacement from the urn, what is the probability that a red ball and a black ball will be selected. Please explain how to do it

Answer 1

First compute all the possibilities:

`15*14=210`
The favorable cases, number of possibilities:

`6*5=30`
Now we get the probability by dividing the above two numbers:

`(30)/(210)=0.14`
The probability that a red ball and a black ball is selected is 0.14.