Prob and stat poker probability question

[Proggy99]

Homework Statement

On average, how many times should Ernie play poker in order to be dealth a straight flush (royal flush included)?

Homework Equations

There are 10 ways to get a straight flush for each suit (ace thru 10 as the starting card), so there are 40 total ways for a straight flush.
There are $$\left(\stackrel{52}{5}\right)$$ different poker hands

So where A is a straight flush, $$p(A) =\frac{40}{\left(\stackrel{52}{5}\right)}=.0000154$$

The Attempt at a Solution

To find the number of times he must play in order to get one straight flush, I am using the equation np = x where x = 1
np = 1
n(.0000154) = 1
n = 1/.0000154 = 64,935.065 times


I am pretty confident in my answer but I do not have the answer to verify this. Can anyone confirm this for me or give me a hint as to where I might be going wrong? Thanks!

 

[chaoseverlasting]

Looks right.

 

[Proggy99]

Looks right.

thanks for taking a look