Level 3
Jade buys a coat, a vest, a sweater and a windbreaker. The average cost of these items is $36. The total cost of the sweater and the windbreaker is ³₅ of the total cost of the coat and the vest. If the coat costs $16.60 and the windbreaker costs $11.50, find the difference in cost between the vest and the sweater.

Level 3
²₃ of Sean's savings comprised of 20-cent coins and 50-cent coins. Sean used some 20-cent coins to purchase a toy. The number of 50-cent coins left was 50% more than the number of 20-cent coins left. Given that Sean had 100 more 50-cent coins than 20-cent coins left in the end, find the amount of money Sean spent on the toy.

Level 3
Annie had ²₃ as many stamps as Becky. The sum of the number of stamps Annie and Becky had was the same as the number of stamps that Callie had. After trading, Callie gave 20% of her stamps to Annie and received 25% of Becky's stamps. If Becky wanted to increase her number of stamps in the end by 25%, find the ratio of her number of stamps to the sum of Annie's and Callie's stamps in the end.

Level 3
Daniel had to solve some Science questions during a 3-week school holidays. At the end of the first week, the ratio of the number of questions solved to the number of questions unsolved was 3 : 7. At the end of the second week, Daniel solved another 36 questions and the number of unsolved questions became ¹₄ of the total number of questions. How many questions did Daniel need to solve on the third week to complete his assignment?

Level 3
Janet wanted to finish reading a 231-page book by the end of the week. On Monday she read ³₇ of the book and by Friday the ratio of the number of pages read to the total number of pages was 9 : 11. Find the number of pages Janet would need to read during the weekend in order for her to complete the entire book.