Three entrants in the Mr. Math Puzzler for March answered all six questions correctly. A couple more got five of six Puzzlers right.

Two of the winners were the Hsu brothers, Eric and Phillip from Crestview Middle School in Chesterfield. The other was 11-year-old Zachary Bian of Grace Christian Academy in St. Louis.

In addition to being named winners in March, all three of them receive $10 book certificates from Borders.

Under the Young Saint Louis.com contest rules, all kids who answer the six questions correctly are mentioned in the answer story. In addition, YSL.com also awards up to three of the winners with the Borders' certificates.

If there were more than three entrants who had answered all the questions correctly, we would have put all their names in a hat a drawn out three.

Of course, the Hsu brothers, 10-year-old Eric and 12-year-old Phillip, have won in previous months. In fact, they've been on a winning streak for all of 2004 so far.

Mr. Math Puzzler is Wayne Hesse, a math teacher at Green Park Lutheran School. He has been helping YSL.com with this extra-curricular math fun since September, 2001.

YSL.com has archived over three years of past issues. That means, you can check up on how Mr. Math Puzzler thinks before you enter the next contest.

Just click on the Past Stories tab at the top of the home page. Then, pick any month after September, 2001. There will be an answer story for each previous month's questions. Check several of them and you'll see the types of questions and answers that Mr. Math Puzzler likes to include.

After checking up, you could be ready for the April questions. Just click here and print out the April entry blank and questions.

But, before that, check the March questions and answers:

February Math Puzzlers answers

1. The capacity of a ferry boat is either 48 children or 36 adults. If 20 children already are on the ferry boat, how many adults still can get on?

Answer: 21

The explanation: This answer can be arrived at by a series of simple calculations. First, we know that 48 children and 36 adults weigh the same. Therefore, if you divide both sides of the 48C = 36A equation by 48, you see that each child equals the weight of 3/4th of an adult. There are already 20 children on the boat so that amounts to the weight of 15 adults. Then, subtract 15 from the 36 adults that would fit on the boat by themselves and you see there's room for 21 more adults.

 

2. Name all the squares with an edge that will touch Square D when the figure below is cut out and folded into a cube.

Answer: A,C,E F

The explanation: You could figure this answer one of two ways. First, you could visualize which edges touch Square D or you could actually cut out the illustration and bend it to see actually which ones touch Square D. Square B is the only one that doesn't touch.

 

3. The length of a rectangle is increased by 10 per cent and its width is decreased by 20 per cent. What percentage more or less is the new area compared with the original area?

Answer: decreased by 12%

The explanation: Area is determined by multiplying length by width or A = LW. So, you multiply Length (which it's increased by 10% or l.l L) by Width (which it is decreased by 20% or .80 W). That leaves the answer at A = .88. That's 12 per cent less area.

 

4. Find all the two-digit numbers that give a sum of 154 when the original number and the number obtained by reversing its digits are added together.

Answer: 59, 68, 77, 86, 95

The explanation: This is one of those "educated guess" answers. You need to try some pairs. For instance, 59 and 95 add to 154. Etc.

 

5. A ball is dropped 128 feet from the roof of a building. Suppose that with each bounce, the ball goes up exactly half its previous height. A man is sitting at his desk on the second floor. How many times will he see the ball (going up or down) if his eye level is 15 feet above the ground?

Answer: 7

The explanation: This Puzzler can be answered by setting up a simple chart with a series of vertical lines. The first line representing the drop from 128 feet. The second line represents the rebound to a height of 64 feet. The third line is when the ball then drops from that 64 feet. The fourth line is when it rebounds to 32 feet. The fifth is for the drop from 32 feet. The sixth sighting is when the ball rebounds to 16 feet. The seventh sighting is the drop from 16 feet. But, then the ball will disappear from the man's view because the next rebound of 8 feet won't reach your eye level at 15 feet above the ground.

 

6. Laura and Sam are having lunch. Laura is paying for the lunch, but she has only $23,92. If she wants to leave a 15 per cent tip, what is the most she can spend on the lunch for the two of them?

Answer: $20.80

The explanation: This answer is a simple algebra equation. The amount of money you have will be 1.15 times the amount of money you can spend for food because you want to leave a 15 per cent tip. Therefore, 1.15X = $23.92. You divide both sides by 1.15 and you get X = $20.80.