both of these are 3, b=3. Therefore, statement II
is true, and you can eliminate choice (A). To find
the average, just divide the sum by 20: ((1)(5)
+(2)(3) +(3)(3) +(4)(3) +(5)(3) +(6)(3))/20 =3.25,
so a=3.25. Therefore, statement I is not true, so
the answer is (B).- B When a 30% solution and a 50% solution are
combined, the concentration must be anywhere
between 30% and 50%, depending on how much
of each you added. It can’t be 50%, though,
because the 30% solution dilutes it.- A If Set A were {0, 0, 10, 10, 10}, then its median,
m,would be 10. Set B would be {2, 2, 12, 12, 12}.
Inspection of Set B shows that it is a counterexam-
ple to statements II and III, leaving (A) as a possible
answer.
CHAPTER 9 / SPECIAL MATH PROBLEMS 341