Your school librarian has asked your class for some help on the purchase of some new bookcases with 2 shelves each. She has 300 new books she needs to shelve. 1/2 of the books are half an inch thick. 1/3 of them are 1/4 of an inch thick, and the rest are three fourths of an inch thick. Her shelves are 30 inches long. How many bookcases should she buy? Show your work.
150 * 1/2 = 75 in
100 * 1/4 = 25 in
50 * 3/4 = 37.5 in
Total inches needed: 137.5
137.5 / 60 = 2.29 = 3 bookcases