Operating Systems - Old Questions

2.  Define the first-fit, best-fit and worst-fit strategies of memory placement. Given memory partitions of 10 k, 4 k, 20 k, 18 k, 7 k, 9 k, 12 k, and 15 k (in order). How would each of first- fit, best fit and worst fit algorithms place processes of 12 k, 10 k and 9 k (in order)? Which algorithms make the best use of memory?