Answer :
Part 1:
3+2+1 = 6 total units
There is only 1 history book.
1/6 total.
Part 2:
6-1 (we've lost the history book) = 5 total units
3 novels. = 3/5
Part 3:
1/6 * 3/5 = 3/30 or 1/10
3+2+1 = 6 total units
There is only 1 history book.
1/6 total.
Part 2:
6-1 (we've lost the history book) = 5 total units
3 novels. = 3/5
Part 3:
1/6 * 3/5 = 3/30 or 1/10