The night before the exam, sleep. A rested mind recalls what a tired one has only read.

Problem Solving — quick quiz

5 SOF IMO-pattern questions on Problem Solving. Instant scoring and solutions, no signup — see where you stand in a few minutes.

Question 1 of 5

Hard

In a class of 50 students, the average weight increases by 1 kg when a student weighing 45 kg is replaced by a new student. What is the weight of the new student?