Of the science books in a certain supply room, 41 are on botany, 65 are on zoology, 90 are on physics. 50 are on geology, and 100 are on chemistry. If science books are removed randomly from the supply room, how many must be removed to ensure that 80 of the books removed are on the same science? Choose the correct choice from the following choices.
A) 81 B) 159 C) 166 D) 315 E) 324
First, you can take all 41 Botany books, all 65 zoology books and all 50 geology books because you're sure to never pick 80 of them.   There are still 90 on physics and 100 on chemistry   The worst case could be that we pick 79 physics and 79 chemistry. So that the next book picked will necessary complete 80 books picked, either in physics or chemistry.   Minimum number of books picked to reach 80 in the same science should be : 41 + 65 + 50 + 79 +79 + 1= 
<gadget id="calculator">41 + 65 + 50 + 79 +79 + 1</gadget>
<output>315</output>
315   315
<result>D</result>
Of the science books in a certain supply room, 41 are on botany, 65 are on zoology, 90 are on physics. 50 are on geology, and 100 are on chemistry. If science books are removed randomly from the supply room, how many must be removed to ensure that 80 of the books removed are on the same science?