Flexbox multiple coumns - html

Question

I need to display a questionnaire with multiple sets of options. When there are only two options, they should be displayed in two columns that have 50% width each. When there are more than two, they should be displayed in three columns that have 33.3333% with each. Currently I'm having a difficulty making the columns to 50% width when there are only two of them.
https://codepen.io/sleepydada/pen/Evjgwr
HTML:
<div class="answers">
<div class="answer">first answer</div>
<div class="answer">second answer</div>
</div>
<div class="answers">
<div class="answer">first answer</div>
<div class="answer">second answer</div>
<div class="answer">third answer</div>
<div class="answer">four answer</div>
</div>
SCSS:
* {
box-sizing: border-box;
}
.answers {
border: 2px solid black;
margin-bottom: 20px;
#media (min-width: 480px) {
display: flex;
flex-wrap: wrap;
justify-content: center;
}
&:first-of-type {
background: #ccc;
}
.answer {
width: 100%;
background: crimson;
margin: 20px 0;
border: 1px solid blue;
#media (min-width: 480px) {
flex: 0 0 33.3333%;
}
}
}

Answer 1

Assuming they should wrap when more than 3 items, here is a pretty cool trick using the nth-child selector and target the items based on how many there are.
Their width is set to a default of 33.333% and then when there is only 2 items, the .answers .answer:first-child:nth-last-child(2) kicks in and make them 50%
* {
box-sizing: border-box;
}
.answers {
border: 2px solid black;
margin-bottom: 20px;
display: flex;
flex-wrap: wrap;
justify-content: center;
}
.answers:first-of-type {
background: #ccc;
}
.answers .answer {
background: crimson;
margin: 20px 0;
border: 1px solid blue;
flex-basis: 33.333%; /* default width is 33% */
}
.answers .answer:first-child:nth-last-child(2),
.answers .answer:first-child:nth-last-child(2) ~ .answer { /* 2 items */
flex-basis: 50%;
}
<div class="answers">
<div class="answer">first answer</div>
<div class="answer">second answer</div>
</div>
<div class="answers">
<div class="answer">first answer</div>
<div class="answer">second answer</div>
<div class="answer">third answer</div>
<div class="answer">four answer</div>
</div>