Step-by-step explanation:
Given that Rita is making a beaded bracelet. She has a collection of 160 blue beads, 80 gray beads, and 240 pink beads. We are to calculate the probability that Rita will need to pick atleast 5 beads before she picks a grey bead from her collection.
Prob for drawing atleast 5 beads before she picks a grey bead from her collection
= 1-Prob for drawing atleast one grey beed in the first 5 draws.
(Because these two are complementary events)
no of grey beeds drawn in first 5 trials is
Bi=(5,1/6)
Prob for drawing atleast one grey beed in the first 5 draws.
=1-Prob of no grey
Hence required prob=P(X=0 in first 5 draws)
= 0.4018
6th beeds onwards can be grey also.
Nearest answer is c)0.45
