I was wondering if somebody could help?

I am working on my coursework for University, and on part of it, I have to calculate the production rate of an excavator. The excavator moves soil at a rate of 1.54m3 per 17 seconds. But this is not the actual real-life working rate as it assumes perfect conditions constantly. For this reason, the quantity needs to be multiplied by 0.7 for a job factor, and also a human factor of 50 minutes per hour.

Thus we have 1.54m3 * 0.7 * 5/6 = 0.898 m3 per 17 seconds. This is the real-life actual output of the excavator.

My question is, rather than calculating the bucket load value, how do I calculate the new time? The time is inversely proportional to the bucket load - the bucket load goes down, so the time would therefore increase. So do I instead divide the time of 17 seconds by 0.7 and 5/6?

Could someone help please?

Thanks