A bag containing 20 disks numbered 1-20 what is the probability you will pick a disk with the numbers 1,2,3,4,5?

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?

Abus travels 36 miles in 45 minutes. enter the number of miles the bus travels in 60 minutes at this rate.

Having a hard time understanding this question (see attachment).