Andrea is selling boxes of cookies door-to-door. On her first
day, she sells 12 boxes of cookies, and she intends to sell 5 more
boxes per day than on the day previous. If she meets her goal
and sells boxes of cookies for a total of 10 days, how many
boxes total did she sell?
A. 314
B. 345
C. 415
D. 474
E. 505