There are

ways of selecting two of the six blocks at random. The probability that one of them contains an error is

So

has probability mass function

These are the only two cases since there is only one error known to exist in the code; any two blocks of code chosen at random must either contain the error or not.
The expected value of finding an error is then
Answer:
x = -7
Step-by-step explanation:
Subtract 15 from both sides of the equation.
x = 8 -15 = -7
Answer:
$12500
Step-by-step explanation:
Given that:
Salary plan 1:
Weekly salary of $500.
And a commission of 4%.
Salary plan 2:
Straight commission of 8%.
To find:
Weekly sales for which both the plans will make the same sales?
Solution:
Let the weekly sales = $
As per question statement:
Salary as per Plan 1 = $500 + 4% of 
Salary as per Plan 2 = 8% of 
Putting both the salaries to equal to find the total weekly sales.
$500 + 4% of
= 8% of 

Therefore, the answer is:
For the sales of $12500, the salary will be same from both the plans.