Let
denote the number of packages brought by customer
. If, for instance,
customers are in line, then the total number of packages is
, and

since the number of packages brought by any customer is independent from the number of packages brought by any other.
a.
is the probability that a total of 3 packages are waiting to get wrapped from among a total of 3 customers. This means each customer must have exactly one package. So

b.
is the probability that a total of 11 packages are brought by 4 customers. The only way for there to be 11 packages is if 3 customers bring 3 packages and the last 1 brings 2. There are
ways this can happen, so

Answer:
I believe it is -17.5. Tell me if I am wrong
Step-by-step explanation:
3x + 5 = x - 10
-x -5 -x -5
2x = -15
x = -7.5
3(7.5) + 5
= 22.5 + 5
= -17.5
Answer:
Add to eliminate y
Step-by-step explanation:
Add to eliminate y
I think it might be 120 but get someone else’s opinion