A maintenance firm has gathered the following information regarding the failure mechanisms for air conditioningsystems: Yes No
Evidence of electrical failure Yes 55 17
Electrical failure No 32 3

The units without evidence of gas leaks or electrical failure showed other types of failure. If this is a representative sample of AC failure, find the probability.

a. That failure involves a gas leak
b. That there is evidence of electrical failure given that there was a gas leak
c. That there is evidence of a gas leak given that there is evidence of electrical failure

A) 0.8131 ≈ 0.81

B) 0.6322 ≈ 0.63

C)  0.7639 ≈ 0.77

Step-by-step explanation:

A)

Total number of  units

= 55 + 32 + 17 + 3

 = 107

hence the probability that the failure involves a gas leak

= ( 55 + 32 ) / 107

= 0.8131

B) probability that there is evidence of electrical failure given tat there is a gas leak

P ( A / B ) =

P( A∩B ) = 55/107 = 0.5140

P ( B ) = ( 55 + 32 ) / 107 = 0.8131

hence P ( A / B ) = 0.5140 / 0.8131 = 0.6322

A = failure due to electrical

B = failure due to gas leak

C)  Probability of a gas leak given that there is evidence of electrical failure

P ( B / A ) =  

P ( B ∩ A ) = 0.5140

P( A ) = ( 55 + 17 ) / 107  = 0.6729

hence P ( B / A ) = 0.5140 / 0.6729 = 0.7639

1/4 because there is 4 grades.

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for