<style>
.test {
color: red;
}
</style>
<form>
<label><input type="radio" name="r" value="1" /> 1</label>
<label><input type="radio" name="r" value="10" /> 10</label>
<label><input type="radio" name="r" value="100" /> 100</label>
<input type="checkbox" name="c" />
</form>
<div>TEST</div>
<script>
document.querySelector('form').addEventListener('change', function() {
document.querySelector('div').classList.toggle('test', this.r.value==10 && this.c.checked)
})
</script>
Не увлекайтесь id.