Question

A bag contains 2 blue, 5 yellow, and 1 black tile. What is the probability of drawing a blue tile followed by a black tile if the first til drawn is not replaced.

A.1/32
B.1/28
C.1/12
D.1/8

Answer 1

B.1/28

Explanation:

The bag contains 2 blue, 5 yellow, and 1 black tile.

The total number of tiles in the bag is

n(S)=2+5+1

n(S)=8

The number of blue tiles in the bag is

n(B)=2

The number of black tile is

n(Bk)=1

The probability of choosing a blue tiles is

`P(B) = (2)/(8) = (1)/(4)`

The probability of choosing a black tile without replacing the first tile is:

`P(Bk)= (1)/(7)`

The probability of drawing a blue tile followed by a black tile if the first tile drawn is not replaced

`P(B\cap Bk) = (1)/(4) * (1)/(7) = (1)/(28)`