Answers for "bootstrap grid examples code"

bootstrap col-md-5 center

<div class="container">
  <div class="row">
     <div class="col-sm-5 mx-auto">
        Centered
    </div>
  </div>
</div>

bootstrap grids examples

<div class="container">
  <div class="row">
    <div class="col-md-8">.col-md-8</div>
    <div class="col-md-4">.col-md-4</div>
  </div>
</div>