Probability Help

Probability Help:
These solved example problems will help you to understand the probability

Example 1: A box contains 8 sixty watts bulbs and 8 hundred watts bulbs. Five bulbs are taken at random. Find the probability of, five will be of the same watts bulbs?

Solution:

Let S = Sample space

A = the event of taking 5 sixty watts bulbs.

B = the event of taking 5 hundred watts bulbs.

(A or B) = The event of taking 5 sixty watts bulbs or 5 hundred watts balls.

i.e. the event of taking 5 bulbs of same watts.

n(S) = ¹⁶C₅ = 4368

n(A) = ⁸C₅ = 56

n(B) = ⁸C₅ = 56 . This could also help us on what is the mean

P(A) = n(A) / n(S) = 56/4368 = 1/78

P(B) = n(B) / n(S) = 56/4368 = 1/78

P(A or B) = P(A) + P(B)

= 1/78 + 1/78 = 2/78 = 1/39

P(A or B) = 1/39