Hi, I was wondering whether someone could help me with a word problem I've been struggling with. Help would be greatly appreciated.

If you(The brilliant solver) needs any more info, please don't hesitate to ask.

Here's the question:

"A group of four girls and some boys(x) go out for coffee to discuss the difficult IEB exam they wrote. After several cups each they calm down and the bill comes to $600. The boys felt generous and split the bill between them.

The result of this that they each pay $25 more than they would have done otherwise. How many boys were there?"