You omitted what it was raised to the power in 1.3 x 10's gallons of water, so i will put it up as 1.3 x 10^15 gallons of water and solve with it
Answer:1,083,333 days
Step-by-step explanation:
Total amount of water held by lake Michigan= 1.3 x 10^15 gallons of water
Amount of water Chicago uses per day =Chicago uses 1.2 x 10^9 gallons of water /day
Therefore,
Number of days water would last if it doesnt rain = Total gallons provided by lake Michigan/ Total gallons consumed per day
=1.3 x 10^15 gallons of water/ 1.2 x 10^9 gallons of water /day
= 1,083,333 days