I found good solution myself. Since slick slider is still used nowadays i'll post my approach.
@RuivBoas answer is partly correct. - It can change the width of the slide but it can break the slider. Why?
Slick slider may exceed browser width. Actual container width is set to value that can accomodate all it's slides.
The best solution for setting slide width is to use width of the actual browser window. It works best with responsive design.
For example 2 slides with absorbed width
CSS
.slick-slide {
width: 50vw;
// for absorbing width from @Ken Wheeler answer
box-sizing: border-box;
}
JS
$(document).on('ready', function () {
$("#container").slick({
variableWidth: true,
slidesToShow: 2,
slidesToScroll: 2
});
});
HTML markup
<div id="container">
<div><img/></div>
<div><img/></div>
<div><img/></div>
</div>