In the first 100 pages there are 10 pages with numbers 40-49 ( that is total of 11 4's) and another 4 in the units, 10's , 20's, .... 90's ( not including 40's) That is total of 9 4's.
So in first 100 pages there are 20 4's.
therefore there are 20 4's on pages 101-200 and another 20 4's on pages 201-300.
On pages 301 to 352 there are 15 4's.
answer is 3*20 + 15 = 75.
