Answer: 4
Explanation:
Given:- Total cds = 68
Total shelves=4
If cds are evenly on 4 shelves then, to find the the number of cds in 1 shelf, we need to divide total cds by total shelves.
Thus, the number of cds in 1 shelf=

If the first shelf containing the letters a-e. if there are 13 cds filed under a-d,
then cds filled under the letter e= 17-13=4
Therefore, cds filled under the letter e=4