Bags of flour come in 3 sizes:

Small bag: A 500 g bag costs 90p.
Medium bag: A 2 kg bag costs £3.40.
Large bag: A 4 kg bag costs £7.60.

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