<meta charset="utf-8">
<h3>¿Alcohol o gasolina?</h3>
<script>
var tanque = 40;
document.write("el consumo de gasolina es:" + (480/tanque) + "km/L");
document.write("<br>")
document.write("el consumo de alcohol/km es:" + (300/tanque) + "km/L");
</script>