During the last four years, a large truck company purchased diesel at…

During the last four years, a large truck company purchased diesel at rates of $1.2, $1.4, $1.5 and $2.1 per gallon. What was the mean cost of diesel over the four-year period if the company spends the same amount of dollars on diesel each year?

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 #14852