3936/9=440 if that is what you meant
Answer:
Speed of boat in still water is 6km/h
Speed of current is 4km/h
Step-by-step explanation:
We know speed = distance / time
Let the speed of boat in still water be x
Let the speed of current be y
Hence the speed of boat, down stream = 
Distance downstream = 20km
Time taken = 2 hours
We have

......(1)
Speed of boat upstream = 
Distance upstream = 4
Time taken = 2
We have

...(2)
Adding (1) & (2)


Substituting in (1) we get

To prove that the subsidiary ledger agrees with the Accounts Payable controlling account balance, complete a B. SCHEDULE OF ACCOUNTS PAYABLE.
The Schedule of Account payable contains the listing of all vendors in the AP ledger that the company currently owes money to. It also includes the current balance of all the accounts payable to the vendors.
For any distribution, the sum of the probabilities of all possible outcomes must be 1. In this case, we have to have

We're told that
, and we're given other probabilities, so we have

The expected number of calls would be
![E[X]=\displaystyle\sum_xx\,P(X=x)](https://tex.z-dn.net/?f=E%5BX%5D%3D%5Cdisplaystyle%5Csum_xx%5C%2CP%28X%3Dx%29)
![E[X]=0\,P(X=0)+1\,P(X=1)+\cdots+4\,P(X=4)](https://tex.z-dn.net/?f=E%5BX%5D%3D0%5C%2CP%28X%3D0%29%2B1%5C%2CP%28X%3D1%29%2B%5Ccdots%2B4%5C%2CP%28X%3D4%29)
![E[X]=1.4](https://tex.z-dn.net/?f=E%5BX%5D%3D1.4)
The answer is 1/q^30 because after simplifying, you can cancel out the p and then you get q^q-20 times q^-10 to get q^-30 which then equals 1/q^30