Why is there an unexplainable gap between these inline-block div elements? [duplicate]

Answer 1

Found a solution not involving Flex, because Flex doesn't work in older Browsers. Example:

.container {
    display:block;
    position:relative;
    height:150px;
    width:1024px;
    margin:0 auto;
    padding:0px;
    border:0px;
    background:#ececec;
    margin-bottom:10px;
    text-align:justify;
    box-sizing:border-box;
    white-space:nowrap;
    font-size:0pt;
    letter-spacing:-1em;
}

.cols {
    display:inline-block;
    position:relative;
    width:32%;
    height:100%;
    margin:0 auto;
    margin-right:2%;
    border:0px;
    background:lightgreen;  
    box-sizing:border-box;
    padding:10px;
    font-size:10pt;
    letter-spacing:normal;
}

.cols:last-child {
    margin-right:0;
}