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The Circle Inscribed In A Parabola Calculus Puzzle – Can You Solve It?

I thank Chad Facciolo for sending me this puzzle! A circle with radius 1 is tangent to two points of the parabola y = x2. What is the area bounded between the inscribed circle and the parabola, as shown in the diagram? Can you figure it out? Watch the video for a solution. Can You … Continue reading The Circle Inscribed In A Parabola Calculus Puzzle – Can You Solve It? Read more ›

Delightfully Fruitful Problem From The Norwegian Math Olympiad – The Cost Of Fruit

Thanks to Oskar for sending me this puzzle! The numbers a, b, and c are positive integers. An apple cost $a, a banana costs $b, and a cherry costs $c. The cost of b apples, b bananas, and a + b cherries is $77. What would be the cost for one apple, two bananas, and … Continue reading Delightfully Fruitful Problem From The Norwegian Math Olympiad – The Cost Of Fruit Read more ›

I Was Wrong – The Kite Problem Correct Proof

A maths test in New Zealand recently made headlines because many students felt it was too hard. Here is one of the so-called impossible problems. The text reads: The kite GDBE is placed in the square ACHF with DG = GB = EG. Calculate the size, x, of angle DBE. Justify your answer with clear … Continue reading I Was Wrong – The Kite Problem Correct Proof Read more ›

Another “Impossible” Math Problem Leaves 15 Year Olds In Tears – New Zealand (Kite Question)

A maths test in New Zealand recently made headlines because many students felt it was too hard. I already covered one problem about a parabola. I was requested to cover another problem about a kite. I have re-created the question: The text reads: The kite GDBE is placed in the square ACHF with DG = … Continue reading Another “Impossible” Math Problem Leaves 15 Year Olds In Tears – New Zealand (Kite Question) Read more ›

Math Problem From China Stumps Internet – Shoes, Cat, Whistle Puzzle Explained

This problem was asked to primary school students in China. This is the latest tricky math puzzle to go viral. Can you figure it out? Watch the video for a solution. Math Problem From China Stumps Internet – Shoes, Cat, Whistle Puzzle Explained Or keep reading for a text explanation. . . . . M … Continue reading Math Problem From China Stumps Internet – Shoes, Cat, Whistle Puzzle Explained Read more ›

Welcome Mental Floss, Readers Digest, And MSN Readers! The Secret Word Puzzle Answer Explained

You might be visiting my site from one of these articles: Mental Floss: Can You Guess the Secret Word in This Brain Teaser? Readers Digest: If You Can Solve the Secret Word In This Logic Puzzle, You Might Be a Genius MSN If You Can Solve the Secret Word In This Logic Puzzle, You Might … Continue reading Welcome Mental Floss, Readers Digest, And MSN Readers! The Secret Word Puzzle Answer Explained Read more ›

Can You Solve Amazon’s Pair Of Socks Puzzle?

This problem was part of a written interview test for Amazon in India. A drawer contains 12 identical black socks and 12 identical white socks. If you pick 2 socks at random, what is the probability of getting a matching pair? Can you figure it out? Watch the video for a solution. Can You Solve … Continue reading Can You Solve Amazon’s Pair Of Socks Puzzle? Read more ›

“Impossible” Question Leaves New Zealand Students In Tears (Parabola)

A maths test in New Zealand is causing a lot of controversy because many students felt it was too hard. The story is getting huge coverage in New Zealand, and it is even getting some coverage in some British and American news outlets. In this post I’ll share one of the “impossible” problems. You can … Continue reading “Impossible” Question Leaves New Zealand Students In Tears (Parabola) Read more ›

The Three Consecutive Numbers Puzzle

This problem was created by Ken Edwards. I have found three consecutive integers such that their product is equal to their sum. What could my numbers be? Solve for all possibilities. Extension: I then came up with a logic puzzle variation of this problem. Alice, Bob and Charlie are stellar students who always solve algebra … Continue reading The Three Consecutive Numbers Puzzle Read more ›

Can You Solve This UK Maths Competition Problem? Fraction Of Factorial Sums And Differences

This is a fun problem that appeared in UKMT, an organization that organizes maths competitions and educational activities. What is the following equal to? Give your answer as an integer. (10! + 9!)(8! + 7!)(6! + 5!)(4! + 3!)(2! + 1!) ———————————————- (10! – 9!)(8! – 7!)(6! – 5!)(4! – 3!)(2! – 1!) I thought … Continue reading Can You Solve This UK Maths Competition Problem? Fraction Of Factorial Sums And Differences Read more ›

Can You This Primary School Math Problem From China? What Is The Time?

This clock displays time accurately like any other 12 hour clock. But this clock has no numbers, and the clock has been rotated out of position. Based on the position of the hour and minute hands, what time is it? You can figure out the exact time. But this problem was presented as a multiple … Continue reading Can You This Primary School Math Problem From China? What Is The Time? Read more ›

Can You Solve The Square’s Side Length Puzzle?

In the square below, a line is drawn from the bottom left corner with length 12 to the interior of the square. From the end of that line, a perpendicular is drawn going up and left with length 3. From the end of that line, another perpendicular is drawn going up and right with length … Continue reading Can You Solve The Square’s Side Length Puzzle? Read more ›

The Octagon In A Parallelogram. Can You Solve This 8th Grade Geometry Problem From Russia?

From each corner of a parallelogram, draw two line segments to connect the corner to the midpoints of the opposite sides. These eight line segments bound an octagon. What is the ratio of the octagon’s area to the parallelogram’s area? This problem was given to 8th graders in Russia for admission to a selective high … Continue reading The Octagon In A Parallelogram. Can You Solve This 8th Grade Geometry Problem From Russia? Read more ›

Baseball’s Home Plate Is Impossible Mathematically

Home base in baseball is a five-sided shape. Rule 2.02 in MLB’s handbook precisely defines how to construct the shape. Home plate is made as a 17 inch square with two corners removed. The top edge is 17 inches, and its two adjacent sides are 8.5 inches. The remaining two sides are defined to be … Continue reading Baseball’s Home Plate Is Impossible Mathematically Read more ›

This Dice Puzzle Stumps Most Mathematicians! The Even Number Rolls To 6 Paradox

You roll a fair dice until you get a 6. What is the expected number of rolls, including the roll of 6, conditioned on the event that all previous rolls (if any) were even numbers? This problem comes from Elchanan Mossel. Mathematician Gil Kalai posted the puzzle to his blog Combinatorics and more and asked … Continue reading This Dice Puzzle Stumps Most Mathematicians! The Even Number Rolls To 6 Paradox Read more ›

Adults Can’t Solve Maths Problem For 12 Year Olds: Tricky Singapore Ribbon PSLE Question

This problem was asked to grade school students in Singapore. “Jess wants 200 ribbons of length 110 centimeters for a party. However, the ribbons were sold at 25 meters per tape. How many tapes will Jess need?” Source: Yahoo News (this might not be the exact wording but it has the key details) Many adults … Continue reading Adults Can’t Solve Maths Problem For 12 Year Olds: Tricky Singapore Ribbon PSLE Question Read more ›

Can You Solve The Sum Of 6s? An “Evil” Math Problem

What is 6 + 66 + 666 + … + 66…6 = ? Each subsequent term in the series has an extra 6, and the last term has the digit 6 repeated 666 times. Watch the video for a solution. Can You Solve The Sum Of 6s? An “Evil” Math Problem Or keep reading. . … Continue reading Can You Solve The Sum Of 6s? An “Evil” Math Problem Read more ›

How Many Rectangles Are There? “Superhumans” Can Solve In 10 Seconds

How many rectangles are in the following grid? How many rectangles are in the following L-shaped grid? These problems appeared on the TV show Superhuman hosted by Kal Penn (Kalpen Modi). The contestant Summer passed the “rectangled challenge”, taking only about 10 seconds to solve each problem. It would seem you have to be a … Continue reading How Many Rectangles Are There? “Superhumans” Can Solve In 10 Seconds Read more ›