Me on this two questions me before tomorrow

Atourist boat is used for sightseeing in a nearby river. the boat travels 2.4 miles downstream and in the same amount of time, it travels 1.8 miles upstream. if the boat travels at an average speed of 21 miles per hour in the still water, find the current of the river.

Ranck the following in order from least precise to most precise

A11 gram sample of a substance that’s used to treat thyroid disorders has a k-value of 0.1247