Find the cost of 500g if 200g cost 40p?

To find the cost of 500g when 200g cost 40p, you first need to determine the cost per gram. Divide the cost of 200g by 200 to get the cost per gram (40p / 200g = 0.2p per gram). Then, multiply the cost per gram by 500g to find the total cost for 500g (0.2p * 500g = 100p). Therefore, the cost of 500g would be 100p.