this means that the 81 people who chose salad were also equivalent to 27% % of all the people surveyed (let's call them "x")
so:
81=27%x
or
81=\(\frac{27}{100}\)x
let's multiply both sides by 100:
8100=27x
and divide by 9:
900=3x
and by 3:
300=x
so we know that all the people surveyed numbered 300!
