PUZZLES AND RIDDLES – PART 8  (Post No.7387)

Written by S NAGARAJAN

Date – 27th December 2019

Post No.7387

contact – swami_48@yahoo.com

pictures are taken from various sources; thanks.

லட்சம் புதிர்கள், விடுகதைகள், மாயாஜால மாஜிக்குகள், புதிர்க் கணக்குகள்! – 8 (81 முதல் 90 முடிய)

ச.நாகராஜன்

1. Problem with Cube

What is the least number of cubical bricks that can be either spread at the form a square or stacked to form a cube?

• Hilary lost one of the cubical building bricks and then found she could make    

only  one solid oblong whereas previously she could make four different ones. How many bricks were there in the complete set?

• John had more building bricks than Hilary. He found he could pack them all  

 together to make a big block in three different ways. How many more bricks did he need to make a solid cube?

• Try these : I have three builder’s bricks, each measuring 9 inches long 4 ½ 

inches wide and 3 inches deep. How many different heights can I build up with them?

• A sash window with a semi-circular top is 2’6” wide. If the top sash is lowered   1 feet what is the area of the opening?
• Arrange six matches together to form four triangles.
• How high is a pole?  :- How high is a pole that casts a shadow 21 feet long, if a six foot man standing beside the pole casts a shadow 4 ½ feet long?
• How deep is a well, if a rope that just reached from bottom to top can be wrapped exactly 12 times around the cylinderical drum of a windlass – the drum being 7 inches in diameter?
• Can you help? My friend Raman who sold carpets said that if he had to multiply two numbers together he usually squared their average instead. The answer was always too big but was near enough, he said. I told him that if he was all that keen on squaring instead of multiplying,, he might as well do a little bit more and get the answer right. What else ought he to do?
•  Take a good look at this number 222221. Is it a prime number?

Answers

1. 64
2. 36
3. Four (to make 64)
4. 14 (using 1, 2 or 3 bricks)
5. 2 ½ square feet – the same as the rectangular overlap.
6. Edges of a triangular pyramid.
7. The pole is 28 feet high. The problem is solved by simple proportion. The height of the pole is to its shadow, 21, as the man 6 is to his shadow 4 ½.
8. The well is a trifle.
9. From his rough answer { (a+b)/2}2 take away the square of half their difference, {(a-b)/2}2. The answer is then ab.
10. No. 222221 = 619 x 359

Thanks : Source 1 to 9 : Mathematics for all by R.Wesley

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