If 10 litres of an oil of Rs.54 per litres be mixed…

If 10 litres of an oil of Rs.54 per litres be mixed with 5 litres of another oil of Rs.66 per litre then what is the rate of mixed oil per litre?

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 #7937