title: How to return the number of trials (n) in a binomial distribution for a given probability using library function scipy.stats.binom.pmf?
body: <p>Is it possible to get <code>scipy.stats.binom.pmf(x, n, p)</code> to return the number of trials (<em>n</em>) with the probabaility, number of successes (<em>x</em>), and probability of successes (<em>p</em>) known?</p>
  
  <p><strong><em>Example Problem:</em></strong> </p>
  
  <p><em>How many throws does Alex need to do in order to be 90% sure of hitting the target at least 10 times?</em></p>
  
  <p>where:</p>
  
  <ul>
  <li>Probability = 0.90</li>
  <li>p = 0.50</li>
  <li>x = 10 </li>
  </ul>