go_away_ira | проценты

Никак не могу найти в интернете подборку задач на проценты на английском языке , но уровня как у Шевкина или уровня сайта www.problems.ru .
На олимпиадных сайтах хорошие задачи встречаются, но уж очень долго их копировать и собирать в один лист.

Problems from Purple comet contest ( authors Titu Andreescu and Jonathan Kane )

Problem 5 A train car held 6000 pounds of mud which was 88 percent water. Then the train car sat in the sun, and some of the water evaporated so that now the mud is only 82 percent water. How many pounds does the mud weigh now?
Problem 11 Aisha went shopping. At the first store she spent 40 percent of her money plus four dollars. At the second store she spent 50 percent of her remaining money plus 5 dollars. At the third store she spent 60 percent of her remaining money plus six dollars. When Aisha was done shopping at the three stores, she had two dollars left. How many dollars did she have with her when she started shopping?
Problem 7 A rectangle has area 1100. If the length is increased by ten percent and the width is decreased by ten percent, what is the area of the new rectangle?
Problem 3 There were 891 people voting at precinct 91. There were 20 percent more female voters than male voters. How many female voters were there?
Problem 8 A rogue spaceship escapes. 54 minutes later the police leave in a spaceship in hot pursuit. If the police spaceship travels 12% faster than the rogue spaceship along the same route, how many minutes will it take for the police to catch up with the rogues?

Problem from Columbus math contest Percent of Population - February 02, 2009

Percent of Population
After a census was taken in 2000 it was found that compared to 1995 the population of Newtonville increased by 20 percent while the population of Kepler City decreased by 10 percent. Also, it was discovered that in 2000 that the two populations were equal. What percent of the 1995 population of Kepler City was the 1995 population of Newtonville?

А также линки на задачи на проценты от Mathcounts