Answer
2065 incoming students need a refresher.
When flipping one side of the proportion, the result is that 4214 incoming students need a refresher. Since this exceeds the total number of incoming students it is not a reasonable answer.
Work Step by Step
Correct:
$\frac{7\ refreshers}{10\ students} = \frac{x\ refreshers}{2950\ students}$
$10x = 2950\times7$
$\frac{10x}{10} = \frac{20650}{10}$
$x = 2065$
Incorrect:
$\frac{7}{10} = \frac{2950}{x}$
$7x = 2950\times10$
$\frac{7x}{7} = \frac{29500}{7}$
$x = 4214$