Lake Michigan holds 13 billion gallons of water. If just Chicago removed water from the lake and it never rained again, how many decades would the water last?

Check explanation section.

Explanation:

In order to be able to answer this question accurately,there is need to follow the formula below for the calculation;

Numbers of decades = total volume/ volume per decade. (1).

So, we are given from the Question above that the volume of water in Lake Michigan = 13 billion gallons of water.

And if chicago uses 5 million gallons of water every decade.

Therefore, using the formula (1) above, we have;

Numbers of decades = 13 × 10^9/ 5 × 10^6 = 2.6 × 10^15 decades.