Mr.
Math Puzzler, Wayne Hesse Answers
to September Puzzlers
We didn't have
any kids who answered all of the September Math Puzzlers correctly.
We had a couple get five of six answers correct.
Below, Mr. Math
Puzzler, Wayne Hesse, has given the right answers together
with explanations of how to find those answers.
As we mentioned,
these Puzzlers can be difficult. But, we hope you had fun
trying and we hope you will encourage your friends to try
the October puzzlers. In fact, why don't you work with your
friends and then each submit an answer.
Remember, all
those answering all the Puzzlers correctly will have their
names listed next month. And, the winning entries will be
put into a hat and up to three $10 Borders book certificates
will be awarded.
Answers
to the September, 2001, Math Puzzlers
1. Which of the
following is the odd one out?
A. CUBE
B. SQUARE
C. SPHERE
D. CYLINDER
E. OCTAHEDRON |
Answer:
B
Explanation:
Except for Square, the other figures are all three-dimensional.
2. If you divide
552 by 1/4, and then divide the result by half of the original
figure, what is the result?
Answer: 8
Explanation:
When dividing by a fraction, you multiply 552 by 4. Then,
you divide that number [2208] by one-half of 552 [or 276]
to get the answer.
3. What is the
answer if, from the numbers below, you multiply by five the
number of even numbers that are immediately followed by an
odd number?
4
7 8 5 3 1 9 7 8 4 4 7 8 9 2 3
Answer:
25
Explanation:
There are five even numbers that are followed by odd numbers.
Then, five times five is 25.
44. What number
should replace the question mark?
5----4 6----7 8----4 9-----3
| | | | | | | |
| 27 | | 40 | | 71 | | ? |
| | | | | | | |
7----6 9----7 5----9 5-----4
Answer:
34
Explanation:
This is a tough one. The secret is to find relationships between
the four numbers on the outer corners that lead to the interior
answer. In this Puzzler, you multiply the numbers in the upper
left and lower right corners (9 x 4=36) and then subtract
the lower left number from the upper right (5 - 3=2). Then,
you subtract 2 from 36 to get the correct answer.
5. Find X.
8 x 7
------------- = X
2/7 - 2/1
|
Answer:
392
Explanation:
Like the answer to Puzzler No. 2, this deals with division
of fractions. Multiply 8 x 7 to get 56 above the line. Then,
2/7 - 2/14= 1/7. To divide 56 by 1/7, you get 392.
6. Find the secret
number by using the six clues.
a. It is
a four-digit whole number.
b. It is greater than 4,000.
c. The sum of its hundreds digit and its ones dig is 9.
d. Twice its tens digit is 2 more than its thousands digit.
e. The sum of one-fifth of its hundreds digit and two-thirds
of its ones digit is 6.
f. Its tens digit is 1 less than its thousands digit. |
Answer:
4039
Explanation:
You can solve this problem by turning it into an algebra problem
where you seek the unknown numbers. The one number you do
know is 4-or-greater. Therefore, you start by giving a letter
designation for the four digits (_a_, _b_ _c_ _d_) and develop
algebra formulas to determine the digits.
Clue B: a>=4,
Clue C: b+d=9, Clue D: 2c=2+a; Clue E: b/5+2d/3=6; Clue F:
c=a-1.
Then, you use
substitution formulas to determine what the first, second,
third and fourth digits are in the answer
