Marianne has been collecting donations for her biscuit stall at the school summer fayre. there are some luxury gift tins of biscuits to be sold at £5 each, normal packets at £1 each, and mini-packs of 2 biscuits at 10p each. she tells amy that she has received exactly 100 donations in total, with a collective value of £100, and that her stock of £1 packets is very low compared with the other items. amy wants to work out how many of each item marianne has. show how she can do it.