Question

A shoebox holds same-size disks. There are 5 red, 6 white, and 7 blue disks. You pick out a disk, record its color, and return it to the box. If you repeat this process 250 times, how many times can you expect to pick either a red or white disk?

Answer 1

Total discs=18
probability of picking red or white disc (in 1 process)=(5+6)/18 = 11/18
probability of getting red or white disc (in 250 times) = (11/18 * 250)/250
=11/18

Answer 2

Answer:

After 250 times, there is a possibility to pick either a red or a white disk for 152 times.

To find:

How many times we can expect to pick either a red or a white disk when we repeat the process for 250 times.

Solution:

Total number of disks are 5+6+7 = 18.

Let’s consider picking disk is red, its probability  = 5/18.

The probability for picking the white disk is = 6/18.

The probability of picking white disk or red disk are

= 6/18+5/18 ( By using the total probability theory)

=11/18.

This process Is repeated by 250 Times, the output will comes on  

$250\times \frac{11}{18} =152$

Thus after 250 times, there is a possibility to pick either a red or a white disk for 152 times.