Average of 15 results is 43

Average of 15 results is 43. If the average of first seven results is 41 and average of last seven results is 45 Then find the eighth result?

Its source gives only the correct option, without the working.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #3284