// add a parameter called hourOfDay to the function
var taxiFare = function (milesTraveled, hourOfDay) {
  var baseFare = 2.50;
  var costPerMile = 2.00;
  var nightSurcharge = 0.50; // 8pm to 6am, every night

  var cost = baseFare + (costPerMile * milesTraveled);
  if (hourOfDay >= 20 || hourOfDay < 6); {
  return cost + nightSurcharge; }
  else { //here's where the error message flags up
  return cost
  }
};