Level 3
Lina, Ron, Evelyn and Henry share the same hobby of collecting stamps. The average number of stamps collected by the 4 friends is 25. Ron collected 8 more stamps than Evelyn but 15 fewer stamps than Lina. Henry collected 3 stamps fewer than Evelyn. Find the average number of stamps collected by Ron, Evelyn and Henry. Round off the answer to the nearest whole number.