Question

A jar contains 5 red marbles, 5 white marbles, and 6 blue marbles. Two marbles are randomly selected from the jar with replacement. Find the following probabilities. Leave your answer as a reduced fraction.

Answer 1

Total number of marbles is 5+5+6=16 marbles

Let the events, $R,W,B$ representing red, white and blue marble selected respectively.

Probability of choosing a red marble is ${5\over16}$

Probability of choosing a white marble is ${5\over16}$  

Probability of choosing a blue marble is ${6\over 16}$

$a)$

The probability that a red marble and then a blue marble is randomly selected is ${5\over16}\times{6\over16}={30\over 256}={15\over`128}$     

$b)$

The probability that a white marble and then a red marble is randomly selected is, ${5\over16}\times{5\over16}={25\over256}$