The average of seven numbers is 20

The average of seven numbers is 20. The average of first three numbers is 14 and the average of last three numbers is 19. What is the middle number?

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 #14126