Answer:
The guard should be positioned at the safe
Step-by-step explanation:
The night watchmen should be positioned to guard whichever place gives the highest expected value to the thief.
The expected value of robbing the safe is:

The expected value of robbing the cash register is:

Therefore, the guard should be positioned at the safe since it yields a higher expected value to the thief in case he tries to rob it.
Answer:
18,176
Step-by-step explanation:
Figure out an easier thing to do: 1000 - 2021 = 9,797.
Therefore, our answer will be like 9999999999999999999999997979. Out of all of these digits, there are only 2 that arent nines. We know the amount of digits since it's 10^2021 power. We will have one less since we are subtracting 2021. Therefore, 2020 digits in total. Now we know of those 2020 digits, 2 of them are 7, therefore 2018 of them are 9s. That means do 2018(9) + 2(7) = 14 + 18,162 = 18,176.
Answer:

And we can find the individual probabilities using the probability mass function
And replacing we got:

Step-by-step explanation:
Previous concepts
The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".
Solution to the problem
Let X the random variable of interest "number of automobiles with both headligths working", on this case we now that:
The probability mass function for the Binomial distribution is given as:
Where (nCx) means combinatory and it's given by this formula:
And for this case we want to find this probability:

And we can find the individual probabilities using the probability mass function
And replacing we got:

Answer:
x=3/7
Step-by-step explanation:
x+4 5/7 = 12x
4 5/7 = 11x
x = 3/7
X+y = 42
x-y = 8
x = 8+y
Substitute it in 1st equation,
8+y+y=42
2y = 34
y = 17
Substitute it in 1st eq.,
x = 42-17 = 25
So, the two numbers are 25 & 17
Hope this helps!