Let

be the number of hours that the waitress works in the evening.
We know for our problem that she works

in the afternoon and that she works <span>1.75 hours less in the afternoon than in the evening, so:
</span>

<span>Since </span>

, we can rewrite our expression:


We can conclude that she works 3.375 hours in the evening, or expressed as a mixed fraction:

hours.