Question

A bag contains x green discs and 5 blue disks. A disc is selected. A second disc is drawn Find, in terms of x, the probability of selecting:
a)A green disc on the first draw
b.A green disc on the first and second draws, if the first disc is replaced.
c) A green disc on the first and second draws, if the first disc is not replaced.

Answer 1

Given:

A bag contains x green discs and 5 blue disks.

To find:

Probability of getting:

a)A green disc on the first draw

b.A green disc on the first and second draws, if the first disc is replaced.

c) A green disc on the first and second draws, if the first disc is not replaced.

Solution:

1) Probability[E]=Number of the favorable outcome / total number of outcomes.

• Number of green discs= x

• Number of Blue discs= 5

• Total discs = x+5

2)P(Green on first draw) = x/x+5

3) P(Green when replaced)  = $(\frac{x}{x+5})(\frac{x}{x+5} )$

                                              = $(\frac{x}{x+5})^{2}$

4) P(Green when not replaced) = $(\frac{x}{x+5})(\frac{x-1}{x+4} )$

The above are the respective probability.