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:
£1.6
Step-by-step explanation:
£20 ÷ £2.3= 8 remainder 1.6
change= £1.6
Answer: He is not correct.
Steps:
Let x1 and x2 be the first and second number, respectively.

In words, if the second is 125%, or 5/4 of the first number (first equation),
then the first is 4/5 of the second, which is 0.8 or 80%.
Answer:
Addition Rule
The word or in probability implies that we use the Addition Rule.
The equation correctly modeled would be
1000+.02t = 15000