Originally Posted by

**e^(i*pi)** The price will be the same in real life but here the question asks the **price per litre**. In other words you'll need to work out the new volume, then divide the price (which is the same) by the new volume

Evidently your new volume is simple 1L + 0.25L = 1.25L while your price remains £1.20

Thus the price per litre is **96p**

(Interestingly it turns out that offer 1 gives you 90p per litre thus making it the better offer)

edit: because I'm bored the equilibrium point (when the two offers are equal in price per litre is 18.03%) - this falls well outside the scope of your question as does everything in red