<div class="w3-row">
    <div class="w3-col m1 w3-container w3-amber">
        <p>a</p>
    </div>

    <div class="w3-col m9  w3-container w3-blue">
        <p>b</p>
    </div>

    <div class="w3-rest w3-container w3-green">
        <p>c</p>
    </div>
</div>