Answer:
18 dollars
Step-by-step explanation: You find 20% of 15 which is 3 and then add 15 and 3.
Answer:
Please see attached
Step-by-step explanation:
Answer:

Step-by-step explanation:
Given
--- rate of hard disk drives failure
--- number of hard disk drives
<em>See comment for complete question</em>
Required

First, calculate the probability that the none of the 4 selected is working;



Using the complement rule, the probability that at least 1 is working is:

This gives:

