Expert: Sherry Wallin - 7/8/2009

Question
1)A number cube(die) is rolled and a coin is tossed.Find the number of outcomes in which an even number is rolled on the cube, and a head is tossed on the coin.

2)Of the Science books in a certain supply room, 50 are on Botany, 90 are on Physics,50 are on Geology and 110 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?

3)A gym class can be divided into 8 teams with an equal number of players in each team or into twelve teams with an equal number of players in each team.What is the least possible number of students in the class?

Answer
Shruti~
   #1 the sample space is:1,H;1,T;2,H;2,T;3,H;3,T;4,H;4,T;5,H;5,T;6,H;6,T so there are 12 possible outcomes and exactly 3/12 = 1/4 of them have an even number and a head.
   #3  You are looking for the least common multiple of 8 and 12 which is 24
   #2 is a tricky question because only the physics books and chemistry have at least 80 books. You are looking at the probability that you have 80 or more chemistry or physics books.

Math Prof