I figured it out how to fix the problem. You need to make the following changes.
1. In mtq_core_Change.min.css change
.items div {
float:left;
}
to
.items div {
float:right;
}
2. Change the two jQuery functions in the script.min.js from left to right:
.animate({left: pos +'px'});
to
.animate({right: pos +'px'});
and
.css({left: pos +'px'});
to
.css({right: pos +'px'});
3. And finally in show_quiz.php change the arrows entity numbers with each other (#8594 and #8592).
Still it would be very nice to have the rtl option in the codes, so that it would automatically apply these changes to the plugin whenever the theme or content is from right to left.