Two methods, A and B, are available for teaching a certain industrial skill. The failure rate is 30% for method A and 10% for method B. Method B is more expensive, however, and hence is used only 20% of the time. (Method A is used the other 80% of the time.) A worker is taught the skill by one of the two methods, but he fails to learn it correctly. What is the probability that he was taught by using method A

Probability that he was taught by using method A is 14/17

Step-by-step explanation:

Following probabilities are given -  

P (F|A) = 0.2

P (F|B) = 0.1

P (A) = 0.7

P (B) = 0.3

Now, P(A|F) = { P (F|A)* P(A)}/{{ P (F|A)* P(A)} + P (F|B)* P(B)}}

P(A|F) = (0.2*0.7)/( (0.2*0.7)+(0.1*0.3)) = 14/17

arithmetic sequence

step-by-step explanation:

given that a sequence has terms as

19, 15, 11,

this is represented on a graph

the pattern indicates that the sequence is an arithmetic sequence with i term

a=19 and common difference d =-4

any general term

thus the sequence is reduced by 4 for each successive term starting from 1 and nth term is

24-5n.

first negative term would start after 5th term

5th term =24-25< 0

from 5th term onwards the sequence would be negative.

add an image

step-by-step explanation: