title: How to add values of common elements in list of lists and make it as one using python?
body: <p>i really need your help to solve my homework. How can i add both list with same element in python?</p>
  
  <p>Example:</p>
  
  <pre class="lang-py prettyprint-override"><code>list = [[5, 'jay'], [20, 'jenny'], [10, 'john'], [13, 'jay'], [10,'jenny']]
  </code></pre>
  
  <p>Output should be like this:</p>
  
  <pre class="lang-py prettyprint-override"><code>list = [[18, 'jay'], [30, 'jenny'], [10, 'john']]
  </code></pre>