## Description
Peter enjoys taking risks, and this time he has decided to take it up a notch!
Peter asks his local barman to pour him **n** shots, after which Peter then puts laxatives in **x** of them. He then turns around and lets the barman shuffle the shots. Peter approaches the shots and drinks **a** of them one at a time. Just one shot is enough to give Peter a runny tummy. What is the probability that Peter doesn't need to run to the loo?
## Task
You are given:
**n** - The total number of shots.
**x** - The number of laxative laden shots.
**a** - The number of shots that peter drinks.
return the probability that Peter won't have the trots after drinking. **n** will always be greater than **x**, and **a** will always be less than **n**.
**You must return the probability rounded to two decimal places i.e. 0.05 or 0.81**
import numpy as np

def get_chance(n, x, a):
    ns = np.arange(n, n-a, -1)
    return np.multiply.reduce((ns - x) / ns).round(2)
import numpy as np

def get_chance(n, x, a):
    ns = np.arange(n, n-a, -1)
    return np.multiply.reduce((ns - x) / ns).round(2)