function orderedByRanking(mainObj) {
  return mainObj.sort((a,b) => (a.ranking > b.ranking) ? 1 : ((b.ranking > a.ranking) ? -1 : 0));
}

function averageRanking(mainObj) {
  let total = 0;
  mainObj.map((a) => (total = total + a.ranking));
  return (total / mainObj.length);
}