I need help on question 7 :)

Imagine a new pasture with grass growing on it. every day after the seeds have germinated, the number of blades of grass in the pasture triples. after 18 days, the entire pasture is completely covered in grass. how many days did it take for the pasture to be one-third covered in grass?

Which is the length of the hypotenuse of the triangle a. 94ft b. 214 ft c. 33ft d. 37 ft

Change negative exponents to positive. then solve. round to four decimal places