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
First compute all the possibilities: [tex]15\times14=210[/tex] The favorable cases, number of possibilities: [tex]6\times5=30[/tex] Now we get the probability by dividing the above two numbers: [tex] \frac{30}{210}=0.14 [/tex] The probability that a red ball and a black ball is selected is 0.14.
