\magnification=1200\hsize=6.5truein \vsize=8.9truein\input eplain
\def\ii#1;{\vglue .8in\vfill\item{#1)} }
\def\ss#1;{\smallskip\itemitem{#1) } }
\noindent {\bf Instructions:} All answers are to be exact; reduce all
rational numbers to lowest terms. Partial credit will be given;
however, I can only grade what I see: show your work.
\bigskip
 
\item{ 1)} John spent \$14.49 on 4.2 pounds of meat. What was the cost per
pound?

\ii 2; If you bought a car for \$3000 (including interest) by  paying
\$318   down and then making 36 equal monthly payments, how much would
each monthly payment be?

\ii 3; Compute ${2\over 7} \times {5\over 6} = {}$

\ii 4; Compute ${5\over 12} + {7\over 20} = {}$

\ii 5; After being reduced 20\%, a bike cost \$182. What was the
original cost?

\ii 6; Suppose a box has 3 blue marbles and 4 red marbles and you 
pick out marbles from the box at random.
        \ss a; What is the probability of picking one marble and it
being red?\bigskip
        \ss b; What is the probability of picking two marbles and them
being the same color?

\vglue .6in\vfill\eject
\item{7)} Suppose an experiment consists in rolling two 6 sided dice.
\ss a; How many elements are in the sample space? \bigskip
\ss b; Explain how to represent the elements of the sample space 
by listing two elements of the sample space. \bigskip
\ss c; What is the probability of rolling less than 6 (i.e., total number of 
dots on upper two faces of the die)? \bigskip
\ss d; What is the probability of rolling less than 8, given that it
is known that the sum rolled is odd?

\ii 8; Suppose 8 out of 40 switches are defective. If you take a
random sample of 3 switches, what is the probability that:
\ss a; they all will be good?
\ss b; they all will be defective?



\ii 9; Let the sample space be the outcomes of flipping a fair coin
6 times.
\ss a; How many elements are in the sample space? \bigskip
\ss b; Give a typical member of the sample space. \bigskip
\ss c; What is the probability of getting two or more heads?

\ii 10; Suppose men and women are equally likely to be born. The
Huang's move in next door. You know that they have two children and 
your sister has just met one of the children, a girl. What is the 
probability that the other child is also a girl? List the elements
in the sample space used to answer this question (explain your 
representation, if necessary).

\bye

