(1 point) A box contains 20 yellow, 33 green and 37 red jelly beans. If 15 jelly beans are selected at random, what is the probability that:

a) 11 are yellow?
b) 11 are yellow and 3 are green?
c) At least one is yellow?

Respuesta :

Answer:

a) Probability that 11 are yellow  = 44/270= 0.163

b) Probability that 11 are yellow and 3 are green = 319/1350= 0.2363

c) Probability that At least one is yellow= 370/1350 = 0.2741

Step-by-step explanation:

Probability of yellow jelly beans =  20/90

Probability of green jelly beans= 33/90

Probability of red jelly beans =37/90

a) Probability that 11 are yellow= (11/15)(20/90)= (11/3)(4/90)=44/270 =0.163

b) Probability that 11 are yellow and 3 are green= 44/270 + (33/90)(3/15)

= 44/270 +11/150= 44(5) + 11(9)/1350= 220+99/1350= 319/1350 =0.2363

C) Probability that at 1 is yellow= 1 - P(red and green)

                                                  = 1- ( 33/90)(14/15) + (37/90) (14/15)

                                                   = 1- (462/1350  + 518/1350)

                                                    = 1- 980/1350= 1350-980/1350= 370/1350 =              =                                                     0.2741