const array = [
  { name: 'Alfred', ranking: 3 },
  { name: 'Boris', ranking: 5 },
  { name: 'Chris', ranking: 2 },
  { name: 'Dylan', ranking: 1 },
  { name: 'Fitzgerald', ranking: 4 }
]

const sortByRanking = () => array.sort((a, b) => a.ranking > b.ranking)

const findAvgRanking = () => (array.reduce((acc, curr) => acc + curr.ranking, 0)) / array.length

console.log(sortByRanking())
console.log(findAvgRanking())