Question

The probability is 1% that an electrical connector that is kept dry fails during the warranty period. If the connector is ever wet, the probability of a failure during the warranty period is 5%. If 90% of the connectors are kept dry and 10% are wet, what proportion of connectors fail during the warranty period?

Answer 1

Answer:

A 1.4% of the total connectors are expected to fail during the warranty period.

Step-by-step explanation:

Let's assume a population of 1000 connectors (to make the math easiest) and let's analize the dry connectors.  

Of the 1000 connectors, 900 are kept dry. and of that number, 9 are the ones that fails during the warranty period.  (90% of 1000 is 900. 1% of 900 is 9)

Of the 1000 connectors, 100 are wet. And of that number, 5 are connectors that will fail during the warranty period. (10% of 1000 is 100, and 5% of 100 is 5)

So overall we have 14 connectors that will fail from 1000 connectors.

That is a 1.4% of the total samples.