BrainDen.com - Brain Teasers 204

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## Everything posted by jasen

1. sorry if my words is confusing. I mean go right (or left) from last position. your answer is close but still wrong. If I draw from your answer, the shape will be a rectangular on a flat surface. _______ | | | x | |_______|
2. create a m x n table. then put the multiplication result of x,y coordinate in each cell. set any cell as your preffered base. from the base go up A steps, then go right (or left) B steps, take the number as num1 from the base go left A steps, then go right (or left) B steps, take the number as num2 from the base go down A steps, then go right (or left) B steps, take the number as num3 from the base go right A steps, then go right (or left) B steps, take the number as num4 (num1 + num2 + num3 + num4) / 4 = your number. anybody can explain this ?
3. Find the digit that each letter represents in the equation MAD * MATH = BRAIN * DEN.
4. look at this interesting sequence : a = 2+1 = 3 b = 2(a)+1 = 7 c = 2(b)+1 = 15 d = 2(c)+1 = 31 e = 2(d)+1 = 63 f = 2(e)+1 = 127 and so on the sequence follow this rule 2(n+1)-1 prove it !
5. B: see 4, there are 2 possibility : 1 x 4 or 2 x 2. so B do not know the 2 numbers so B first say "No" A: see 5, there are 2 possibility : 1 + 4 or 2 + 3. From B answer, A still can't deduce the 2 numbers. if B see 6 (2*3) B will say No (2 possibility 1*6,2*3) if B see 4 (1*4) B will say No (2 possibility 1*4,2*2) so A say "No" B: From A answer if A see 4 from (2*2) there are 2 possibility : 1 + 3 or 2 + 2. but A must say yes, because if the numbers are 1 and 3, B will answer "yes" imediately so A must deduce the numbers are 2 and 2 in the first try. So A must be see 5, and B deduce the numbers must be 1 and 4
6. I was inactive for 4 days. @TimeSpaceLightForce Using time is the right answer, but they don't need that long. If they can measure the time accurately, both using accurate watch, the first man can inform the number not more than 2 minute.
7. Ok, maybe my question is not specific enough. - There is only one room, not hotel. - The man inside the room, is giving information to his friend outside the room, by pushing the bell button once. - there is only 1 bell, and it just ring, not stated something. - The man inside the room, can't control how long the bel ring. - the number is between 0 and 100.
8. A man enter a room. In the room there is a 2 digits number on the wall. His friend outside the room do not know the number. But just by ring the bell once, his friend know the number. how could this happen ?
9. Very good start, your second answer is right, but the first answer is wrong, because 1+6+9+5+12 =/= 10+4+2+8+3. We can easily find the other right answer from the first right answer. use your second answer to find another right answer (ofcourse without rotation and reflection) hint : put the inner points to the outer points.
10. I think, "conservation of mass and energy" law is a paradox. Because if mass and energy can't be created, then you and me should not exist.
11. Put numbers 1,2,3,4,5,6,8,9,10,12 each point, so : - The sum of points in every line are equal, - A+B+C+D+E = D+E+F+G+H There are 2 solutions. (Rotation and Reflection are considered as 1 same solution)
12. Some more years, I will turned x years of age in the year x2. How old I'm now ? (I'm not using miraculous anti-aging treatment now.)
13. @bonanova. How do you get the numbers? My answer is very close to your answer for 6 digits numbers. If I search the numbers by computer start from 000000 to 999999 the result is exactly same with your calculation. (although maybe it is not the best answer) ["000000","011111","022222","033333","044444","055555","066666","077777","088888","099999","101234","110325","123016", "132107","145670","154761","167452","176543","202318","213209","220153","231042","246735","257624","264580","275491","303145","312054", "321360","330271","347506","356417","365723","374632","404826","415937","428405","439514","480649","491758","506951","517840","529687","538796", "581473","590562","608579","619468","626894","637985","684257","695346","724978","735869","748021","759130","786302","797213","842963", "853872","962831","973920"]
14. Find the maximum number of distinct ways you can create combination of six digit number (from 0 through 9). with following rules : 1. Each number can be used more than one. 2. Any two combinations can have at most 1 digit in same place. example : a. 075922 and 166433 is accepted. b. 075922 and 166432 is accepted, both put 2 in 6th place). c. 075922 and 066432 cannot both be used, because both put 0 in first place, and 2 in 6th place).
15. First count (sqrt 5), in very high precision. Then use pascal triangle formula. then group every odd exponent of sqrt (5). then multiple it by (sqrt 5) just once, you will get right answer. you will get better precision. example (a+b)5 = a5 + 5a4b + 10a3b2 + 10a2b3 + 5ab4 + b5 = a5 + b(5a4 + 10a2b2 +b4) + 10a3b2 + 5ab4 (3 + √5)5 = 35 + √5(5.34 + 10.32.5 + 25) + 10.33.5+ 5.3.25 = 1968 + √5*880
16. Ask the bank's guard to take the gold bar for you, then you can go to the bank by bus. or ask someone else to take the gold bar for you, then you can go to the bank by bus. They can bring the gold bar by other vehicle.
17. 1st hint : all the numbers are 2 raised to the power of something. (2 = 21, 4 = 22, 8 = 23, 32 = 24) 2nd hint : Use exponent laws Exponent Laws: xm * xn = xm+n
18. You meet 4 persons, at least one of them always tell the truth, and the other always lie. Then you have conversation with them. Andre : I, Brian and Cole are truth-tellers, Diego is a liar. Brian : I'm truth-teller, Andre and Cole are liars. Cole : I, and Andre are truth-tellers, other are liars. Diego : I, and Andre are truth-tellers, Brian is a liar. Identify the liars and truth-tellers.
19. Another "Easy" Puzzle Find The value of x and y, then put numbers 2,4,8,32,x,y to each point, so : I. The product of points in every circle are equal, (A*E*F*C = B*E*D*C = A*D*F*B) II. A*B*C = D*E*F There are 2 solutions (Reflection and rotation solutions are considered as 1 same solution)
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