Let's write it down:
"60 is 75% of s" means:
60=75%*s
75% is \(\frac{75}{100}= \frac{3}{4}\), (percent just means "out of 100" so we just divide it by 100) so we can also write:
60=\(\frac{3}{4}\)s
now, let's multiply both sides by 4:
240=3s
and divide by 3:
80=s
So we have the result that the original value, s, is 80!