The manager of the school bookstore ordered 180 boxes of pencils. Based on the average daily use, she knows that the pencils will last about 30 days. Which linear equation represents the situation?

How many boxes of pencils should the manager expect to have after 20 days?

A. y = - 6x + 180; 120 boxes

B. y = - 6x + 180; 60 boxes

C. y = 6x + 180; 120 boxes

D. y = 6x - 180; 60 boxes

Will give 26 points!!​