JSFiddle - React, Tailwind, and code Playground
HTML
<div data-num="N" class="col-lg-9 questionDetails" style="display: none">
</div>
JavaScript
function questionDetailsShow(newIndex) {
$(".questionDetails [data-num=newIndex]").show();
}
<div data-num="N" class="col-lg-9 questionDetails" style="display: none">
</div>
function questionDetailsShow(newIndex) {
$(".questionDetails [data-num=newIndex]").show();
}