The average student age of a certain class which has 30 students…

The average student age of a certain class which has 30 students is 10. If one student aged 11 go to another class and the age of the class teacher is included the average changes to 11. What is the age of class teacher?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #34415