Submitting oldest living parent assignment.

It makes an object containing all the parents as keys, and then uses that object to filter the people array down to just the parents, where it then picks out the highest age by comparing the ages to the saved highest age (so far). 
the only effeciency i can think of here is your solution runs at O(n^2) no matter what. using sorted data structure and  a for loop might save some work for the second loop which could improve the best case effeciency