Two contestants answered all six Math Puzzler questions correctly in the February competition. Both also were winners in the January contest.

Tim Hakenewerth of Immaculate Conception School in Old Monroe won again as did a girl from St. Gabriel's School in south St. Louis. The girl winner didn't want her name listed on the internet.

Since there were two winners, both will receive $10 Border's gift certificates.

Young Saint Louis.com awards up to three gift certificates each month. Since there were only two winners, they both get the certificates.

Remember, all kids ages 8 to 13 in the St. Louis metro area can enter this Math Puzzler fun competition.

Mr. Math Puzzler is math teacher Wayne Hesse of Green Park Lutheran School in south St. Louis County. He picks math questions that are both fun and illustrate important math principles.

The questions can be difficult, especially for younger kids. But, YSL.com doesn't mind if you get some help from your parents or older brothers and sisters. You might like to get some friends together and figure out the answers as a group.

Then, each of you could submit your own entry form. Or you could compete within your group and come up with different answers.

Mr. Math Puzzler believes that if you have fun with math, you're more likely to get to understand math principles. No one said math had to be totally serious.

To enter the March competition, just click here for the new Puzzlers.

Math Puzzlers for February, 2003

1. Which of the following is the odd word out? The difference has nothing to do with letters or syllables.

cube     square     pyramid     sphere

Answer: Square

Explanation: The square is the only two-dimensional figure. The others have three dimensions- height, width and depth.

 

2. The store owner didn't want to be left with any snow shovels after winter. A shovel that originally cost $40 was reduced by 20% on January 1. On February 1, he reduced the price 50%. What is the present price of a snow shovel?

Answer: $16

Explanation: On the first price reduction, the $40 shovel was reduced to $32. On the second price reduction, the $32 shovel was reduced to $16. In formula form, that would be (40x.8) x .5= 16.

 

3. Every day a cart is sent from a village to meet a barge at the river dock. One day, the barge arrived early and the cargo normally picked up by the cart was immediately sent toward the village by horse. The cart driver left the village at the usual time and met the rider along the way, after the rider had traveled for 8 minutes. The rider handed the load to the cart driver, who went back to the village, arriving home 24 minutes earlier than usual. How many minutes early was the barge? (Be careful.)

Answer: 20 minutes

Explanation: This is an answer that can be found by starting with any time on the clock. For our purposes, let's say the cart driver and the rider met at Noon. That meant the rider left from the barge eight minutes earlier, or 11:52 a.m. Since the cart driver arrived back at the village 24 minutes earlier, that means it would have taken him 12 more minutes to go from the place he met the river to the barge. That means he would have arrived at 12:12 p.m. Then you add the cart driver's 12 minutes to the rider's 8 minutes, it means the barge got in 20 minutes early.

 

4. A knight has ridden one-third the total distance of his trip when his horse becomes lame. He finished the journey on foot, spending twenty times as long walking as he had spent riding. How many times faster was his riding speed than his walking speed? (Hints: Draw a diagram. Put in some values to test your theory.)

Answer: 10 times as fast

Explanation: In this problem, you can use any numbers for time and distance of the trip. If you assign five miles to the one-third leg the knight rode, that means the two-thirds leg would be 10 miles. If you assign two hours for the distance, the knight rode, it would mean the two-thirds leg would take 20 times the time. You figure the relative speeds this way:

The riding rate        Distance Rate = --------         Time          5 miles Rate = -------        2 hours   Rate = 2.5 mph

The walking rate        Distance Rate = --------         Time          10 miles Rate = --------        40 hours   Rate = .25 mph (or 10 times slower)

 

5. "How old are you, Professor Smith?" asked one of his brighter students.
     The professor answered with a riddle, "I am three times my son's age, and my father's age is four years more than twice my age. Together the three of us are a mere 124 years old."
     How old is Professor Smith?

Answer: 36 years old

Explanation: We need a formula for the son, the professor and the father.

The son is S; the professor is 3S, and the father is 4 + 2(3S)

The overall formula is:

4 +2(3S) + 3S + S = 124

          4 + 10S = 124
         -4          -4
         --------------
              10S = 120

                S = 12

Therefore: Son's age (S) is 12; professor's age (3S) is 36 and his father's age (4 + 2(3S)) is 76.

 

6. Can you uncover the logic used to place each of the numbers below? If so, what number should be placed at the question mark?

Answer: 3

Explanation: The relationship in the numbers is the number of times a rectangle is overlaid by surrounding rectangles. The one with the ? is the only one that is overlain three times.