If the average (arithmetic mean) of the four numbers K, 3K +…

If the average (arithmetic mean) of the four numbers K, 3K + 3, 3K – 4 and 5K + 1 is 60, what is the value of K?

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 #48940