I’m currently revising for my maths gcse, and have come across this question in my book. I’ve been stuck on it for about half an hour, every answer I get is wrong to the answer they provide on the answer page. Could someone help ?

“Ismail bought a smart phone and a laptop. The total cost, including VAT at a rate of 20%, was £684. The price of the smart phone excluding VAT was £250.
What was the price of the laptop excluding VAT?”

The answer the book provides is £320, but every time I’ve tried to work it out I end up with £297.20.