payout.cljs

(defn- average [coll]
  (/ (reduce + coll) (count coll)))

(let [paid              {:karan   900
                         :chirag  50
                         :jindi   400
                         :harleen 200
                         :sukh    100
                         :raman   10}

      [min-key min-amt] (apply min-key val paid)
      [max-key max-amt] (apply max-key val paid)

      avg-cost          (average (vals paid))

      owed              (->> paid
                             (map (fn [[k v]]
                                    [k (-> (- v avg-cost)
                                           int)]))
                             (into {}))]
  owed)