"A" sort a particular dataset of size n using merge sort takes time = 640 msec,
we know that time complexity of merge sort = O(nlogn) = c1. nlogn
so 640 = c1. nlogn -(1)
"B" uses the same algorithm on dataset of size 16 takes = 25 msec
256 = c1. nlogn [here we know n = 16]
256 = c1. 16 log16
c1= 4
Put value of c1= 4 in (1)
We get answer as 32.