For the first time in several months, we didn't have a winner in the April Mr. Math Puzzler contest. Even the Hsu brothers from Chesterfield had an off month.

Several entrants got five of the six Puzzlers correct. But, no one got all six.

As you know, Eric and Phillip Hsu have had winning entries for the first three months of 2004. But, in April, both of the boys missed one Puzzler, getting five of the six correct.

There weren't as many entrants during April, probably because of spring breaks for most of the schools in the St. Louis metro area.

But, now that school is back in session, it would be a good time to pick up the habit of having fun with the Mr. Math Puzzler questions.

Mr. Math Puzzler is Wayne Hesse, a math teacher at Green Park Lutheran School.

For years, he has given his math students fun questions to do if they get all their assignments ahead of time. The purpose of the "extra credit" questions is to encourage them to think of math as a fun thing to do, not just homework.

That's the type of questions he's been doing for Young Saint Louis.com since September, 2001.

That means he's created nearly 200 Math Puzzlers for your enjoyment.

You can sample some of the past Puzzlers. And by using the next month's answers, you can get better understanding of math. (You can find the past Puzzlers by clicking on the Past Stories tab on the home page and looking at any edition from September, 2001, to the present.)

Mr. Math Puzzler tries to take his questions from real life situations. That way, you'll be able to see how math fits into your everyday life. And Mr. Hesse also encourages you to try "educated guesses" when trying to find the answers.

Before entering the May, 2004, Puzzler competition, sample some of the past issues and find out how Mr. Math Puzzler thinks.

Then, when you think your reading, click here for the entry form for the May contest.

The April Math Puzzler answers:

1. The area of a nine-meter square is how much larger than the area of a square containing nine square meters?

Answer: 72 square meters

The explanation: A 9-meter by 9-meter square contains 81 square meters. Then, subtracting the nine square meters from the smaller square, the answer is 72 more square meters.

 

2. Lisa and Ruth each have $10 in the bank. Every month, Lisa plans to add $1 to her account. Ruth plans to add $3 to her account every month. If you don't consider interest, in how many months will Ruth have twice as much money as Lisa?

Answer: 10 months

The explanation: This is a good place to use a chart to figure the answer.

Month	Lisa	Ruth
0	$10	$10
1	$11	$13
2	$12	$16
3	$13	$19
4	$14	$22
5	$15	$25
6	$16	$28
7	$17	$31
8	$18	$34
9	$19	$37
10	$20	$40

 

3. On a prime day, the month and the day are both prime numbers. How many prime days will occur in the year 2004?

Answer: 53 days

The explanation: There are five prime months in the year, February (2), March (3), May (5), July (7) and November (11) There are a maximum of 11 prime days in a month, depending on the length of the month. (2, 3, 5, 7, 11, 13, 17, 19, 23, 29 and 31). In February, there are 10 prime days; in March, 11; in May, 11; in July 11 and in November 10. (If you happened to have counted 52 prime days in prime months, you probably didn't figure February 2004 as a Leap Year with an extra prime day.)

 

4. Assuming that both boy and girl births are equally likely, which is more common in a family of four children: an equal or unequal number of boys and girls. Or is neither more common?

Answer: Unequal

The explanation: This is a probability question and Mr. Math Puzzler recommends using a tree diagram to find the answer.

Following the arms of the tree diagram, you'll find that six of the 16 possibilities end up with two boys and two girls in a family. The other 10 possibilities involve an unequal number of boys and girls. (The check marks on the right side of the tree show the families with two boys and two girls.)

 

5. A quantity of dirt can be moved by people in 12 days, by horses in 4 days and by a steam engine in 2 days. If all work together, how long will it take to move that quantity of dirt?

Answer: 1.2 days

The explanation: This answer can be arrived at with a combination formula. A person would move 1/12th of the dirt in a day; the horse would move 1/4 of the dirt in a day, and the steam engine would move 1/2 the dirt in a day.

1/12 + 1/4 + 1/2 = X

1/12 + 3/12 + 6/12 = 10/12 or 5/6

The three together would move 5/6th of the dirt in one day. To move the other 1/6th of the dirt would take 1/5 of an additional day. Therefore, the answer is 1.2 days.

 

6. If 3@7=1 and 4@2=2 and 9@15=3 and 8@12=4 and 10@20=10, then what is 6@6?

Answer: 6

The explanation: The @ stands for a greater common factor, the biggest number that goes into both numbers. The biggest number on the final 6@6 equals 6.