Question

.1.In a large bag of marbles, 25% of them are red. A child chooses 4 marbles from this bag. If the child chooses the marbles at random, what is the chance that the child gets exactly three red marbles? . A) 0.047. B) 0.141 . C) 0.211 . D) 0.063. . 2.A pet supplier has a stock of parakeets of which 10% are blue parakeets. A pet store orders 3 parakeets from this supplier. If the supplier selects the parakeets at random, what is the chance that the pet store gets exactly one blue parakeet?. A) 0.081 . B) 0.243 . C) 0.027 . D) 0.003 . In a large bag of marbles, 25% of them are red. A child chooses 4 marbles

Answer 1

A: 0.047

B: 0.243

Explanation:

A:

`(4!)/(3!(4-3)!) (0.25)^(3) (1-0.25)^(4-3)`

= 0.0468 ≈ 0.047

B:

The probability of a blue parakeet to be chosen is 0.10 and the probability of a non blue parakeet is 0.90.

We can conclude from the given situation, the following combinations:

No blue parakeet:
`0.90^(3)= 0.729`

If 1 blue parakeet is selected:
`0.90^(2)*0.10= 0.081`

When there are 2 blue parakeets:
`0.90*0.10^(2) =0.009`

When 3 blue parakeets:
`0.10^(3) =0.001`

So,the chance that the pet store gets exactly one blue parakeet is given by:

`0.081*3 =0.243`

Answer 2

1. Your question tells that the percentage of the red marble in the bag is 25%. So if a child chooses 4 marbles, the probability that he could get 3 red marbles is A.0.047
2.In your question the supplier has a stock of parakeets were 10% is blue, so the chance of the supplier to deliver 1 blue parakeet out of 3 is letter B.0.243