Prevent div from wrapping to next line

http://stackoverflow.com/questions/29311558/prevent-div-from-wrapping-to-next-line

HTML

<div id="container">
    <div class="right">-other stuff-</div>
    <div class="left">this is an expanding area of text</div>
</div>

CSS

#container {
    width: 250px;
    margin: 0 auto;
}

.right {
    float: right;
}
.left {
    overflow: hidden;
    white-space: nowrap;
}