Answer
2 people ordered poached eggs.
When flipping one side of the proportion the result, 2000 people ordered poached eggs, is unreasonable because it exceeds the number of people who ate in the restaurant.
Work Step by Step
Correct
$\frac{3\ like\ poached}{100\ people} = \frac{x\ like\ poached}{60\ people}$
$100x = 3\times60$
$\frac{100x}{100} = \frac{180}{100}$
$x = 2$
Incorrect
$\frac{3}{100} = \frac{60}{x}$
$3x = 100\times60$
$\frac{3x}{3} = \frac{6000}{3}$
$x = 2000$
