4. A tank, which initially contained 80 liters of water, is being drained at a rate of 2.5 liters per minute.
How many liters of water remain in the tank after the following amounts of time?
30 seconds
a.
b.
7 minutes
c.
t minutes.

1- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis.2- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in the first question?