Searching in Array

#1

We cannot apply binary search in unsorted array . Do We have to implement binary search in this problem?
Can we search the element using linear search with time complexity O(n)?

#2

Rahul had a sorted array of numbers from which he had to find a given number quickly

the arrays are already sorted

#3

rotation does not change the order of elements(if they are in increasing order then after rotation they are now in decreasing order). Is this Concept used here?