Respuesta :
Answer:
0.1978 is the probability that at least 5 keyboards will have mechanical defect.
Step-by-step explanation:
Solution:
Given:
A repair facility has 25 failed keyboards.
10 keyboards have electrical defect.
15 of which have mechanical defect.
Randomly selected keyboard= 6
The set of A is the set of keyboards with electrical defect.
And the set of B is set of keyboards with mechanical defect.
N(A U B) = n (A) + n(B) – n (A ∩B)
Probability of at least 5 will have mechanical defect is:
= p( 5 mechanical defect U 6 mechanical defect)
= p(5 mechanical defect ) + p(6 mechanical defect)
=(15 C 5 x 10 C1 + 15 C6 X 10C0) / 25 C6
= 3003 X 10 / 177100 + 5005 X 1 / 177100
= 30030 + 5005 / 177100
= 35035 / 177100
= 0.1978
0.1978 is the probability that at least 5 keyboards will have mechanical defect.
