Kiersten runs a website that people learn to programme. every month, kiersten receives a subscription fee of a 10 from each of the subscribers to her website. last month, the website had 100 subscribers. this month, 30 new members joined the website, and 10 members cancelled their subscription. how much money will kiersten’s online business earn this month?

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.