Blow up a balloon, tie the string tightly around the neck of the balloon many times, look at the balloon everyday to see if it has changed the size, can you think of an explanation of what you have observed, write down your explanation

Aswimming pool whose volume is 10 comma 000 gal contains water that is 0.01% chlorine. starting at tequals0, city water containing 0.003% chlorine is pumped into the pool at a rate of 5 gal/min. the pool water flows out at the same rate. what is the percentage of chlorine in the pool after 1 hour? when will the pool water be 0.006% chlorine?