The average age of a group of n people is 15 years…

The average age of a group of n people is 15 years old. One more person aged 35 joins the group and the new average is 17 years old. What is the value of n?

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 #46051