This is a simultaneous equation right here. We can start off by converting the question into something more recognisable, and hopefully that will help you to be able to solve this on your own. If you’re still struggling however, please just write a comment and I can talk you through it.
First, let’s convert this to a recognisable formula. We’ll call IPads X and Laptops Y. It doesn’t really matter why I called it X and Y, it could be A and B, all that matters is that we’re actually giving them an identity.
The two formulas which we can then produce are:
4X+3Y = 855
3X+5Y = 1150
This should be much more like the textbook questions which you are used to. Hope this helps, and if not, please message me for further explanation. :)