Bags of sugar come in 3 sizes:

Small bag: A 250 g bag costs 85p.
Medium bag: A 500 g bag costs £1.90.
Large bag: A 3 kg bag costs £3.90.

Calculate the cost of 3 kg for the small and medium bags.
Give your answer in pounds to 2 dp.
Write the bag that is the better value in the comments.