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Brain Teasers

Mind challenges.

Brain Teaser – Ships

There are 5 ships in a port

Brain Teaser – A Book

A book has N pages, numbered the usual way, from 1 to N. The total number of digits in the page numbers is 1,095. How many pages does the book have?

Calculate the velocity of water coming out of a double-entry pipe

If we know the volumetric flow rates of the water going into the two branches, then what would be the velocity of the water coming out?

New Brain Teaser – What is that number?

There is a number less than 3000 that when divided by 2 leaves a remainder of  1, when divided by 3 leaves a remainder of 2, when divided by 4 leaves a remainder of 3, When divided by 5 leaves a remainder of 4, when divided by 6 leaves a …

3 Questions for an Engineer

1. How much does a house weigh? 2. How much weight can a rural two-lane bridge hold? Click to Zoom 3. And finally, would this be covered under the home insurance or the car insurance policy?

Brain Teaser: Fill in the Blanks

Four words with the letters SNT, in that order, have all their other letters removed. You must use the letters below to fill in the blanks. _ _ S _ N T _ _ _ S _ _ N T S _ N _ _ T S _ _ _ N T Letters to use: A, A, E, E, E, I, I, L, L, Q, S, S, U, U

A 25 ft ladder (assume it is not an extension ladder) is placed with its foot 7 ft away from a building. If the top of the ladder slips down 4 ft, how many feet will the bottom slide out?

Brain Teaser – An 8-inch model screw

An 8-inch model screw, tested in a water tunnel at a rotational speed of 22.5 revolutions per second and a velocity of flow of 12 feet per second, yields a measured thrust of 28.5 pounds, a torque of 3.45 pounds and an efficiency of 70 per cent. If the model …