Question

the probability of selecting a red ball at random from a jar that contains red, blue and orange ballis 1 upon 4. the probability of selecting a blue ball at random from a jar is 1 upon 3. if the jar contains 10 Orange balls. find the total number of balls in the jar???

Answer 1

Let there be x balls in the jar

We are given, P(red ball) = 1/4
                       P(blue ball) = 1/3
                       P (Orange ball) = 10/x

so, P(red ball) + P(blue ball) +P(Orange ball) = 1
          1/4 + 1/3 + 10/x = 1
             so,     3x+4x+120/12x = 1
                    7x+120 = 12x
                 so, x = 24

So, there are 24 balls in the jar