AMO · 2027 · Grades 6-7 · Self-study SET 23 Question 13

I have a set of four numbers $P,Q,R,S$ in ascending order. The average of $P,Q,R$ is 22, and the average of $Q,R,S$ is 24. The largest number is 27. Then the smallest number in this set:

**Input:** Choose one option.