Question

a construction worker measures the amount of cement in a cement truck every 5 minutes as it empties what is the rate of change for the volume of cement in the truck

Answer 1

That's exactly what he's measuring. So we can't tell,
because you haven't told us any of his measurements.

The rate of change during any 5-minute period would be

(the difference between two of his measurements)
divided by
(5 minutes)

probably in units of [cubic yards per minute].