In order to find this, we first subtract the 45 from the 160:
160−45=115
Then, we divide the 115 by 160:
115/160=0.718
Which means 72% of them are NOT stamps with presidents on them. Since we're looking for
100%, we'd just subtract 100 by 72:
100−72=28
That means that 28% of the 100% of the stamps are presidential stamps.