9514 1404 393
Answer:
- X X X X X X X
 - Y Y Y Y Y
 - Z Z Z
 
Explanation:
There are 20 rectangles, so 35% of them is ...
 0.35 × 20 = 7 . . . . will be marked with X
25% of them is ...
 0.25 × 20 = 5 . . . . will be marked with Y
15% of them is ...
 0.15 × 20 = 3 . . . . will be marked with Z
_____
Additional comment
The total number of markings is 7+5+3 = 15, which is fewer than the number of rectangles. Consequently, it is not necessary to put more than one mark in any given rectangle, unless you just want to .