If the following stack of blocks looks the same from back and front directions, what is the number of blocks that are used to build it?
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Answer:
70
Friday, January 27, 2012
Saturday, January 21, 2012
Pulleys Puzzle
In the following figure, the diameter of pulley P1 is twice that of pulley P2, as the diameter of pulley P3 is twice that of pulley P4. If pulley P3 rotates 15 times, how many times will pulley P1 rotate?
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Scroll down to see the answer!
Answer: 8 times.
Pulley P4 rotates 30 times; while its pinion with 8 teeth rotates 30 times too (30 * 8 = 240 teeth-based rotations). The pinion of pulley P2 has 15 teeth; so it rotates 240 / 15 = 16 times that makes pulley P1 rotate 8 times!
Pinion Puzzle [Easy 1]
If pinion A rotates six times how many times will pinion C rotate?
Answer:
10.
A has 20 teeth and B has 10. So B rotates 12 times. As C has 12 teeth, B has 10 teeth, and B rotates 12 times, C will rotate 10 times: 12 * 10 = 10 * 12.
Or, simply:
6 * 20 = 120
120 / 12 = 10
Scroll down to see the answer!
Answer:
A has 20 teeth and B has 10. So B rotates 12 times. As C has 12 teeth, B has 10 teeth, and B rotates 12 times, C will rotate 10 times: 12 * 10 = 10 * 12.
Or, simply:
6 * 20 = 120
120 / 12 = 10
Friday, January 20, 2012
Visual Memory Test
In the following figure, there are 10 letters connected by pieces of lines. Study this figure for 2 minutes to remember what pairs of letters are connected to each other:
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Three connections are removed from the above figure and the remaining ones are depicted as in the following:
Can you remember the connections of which pairs of letters are removed?
Answer:
Monday, January 16, 2012
The Odd Ball Problem
You are given twelve balls identical in appearance but one of which is either heavier or lighter than the other eleven balls. You are allowed three weighings with a balance to determine which one is the odd ball and to find whether this ball is heavier or lighter than the others. How do you detect the odd ball?
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Solution:
This is a solution presented by "BRIAN D. BUNDY":
Scroll down to see a solution!
Solution:
This is a solution presented by "BRIAN D. BUNDY":
We may label the balls 1, 2, ..., 12 so that we can distinguish between and identify them using these labels.
1. 1. Weigh 1, 2, 3, 4 against 5, 6, 7, 8.
- They balance, so 9, 10, 11, 12 contain the odd ball. Weigh 6, 7, 8 against 9, 10, 11.
- They balance, therefore 12 is the odd ball and so weigh 12 against any other to discover whether it is heavy or light.
- 9, 10, 11 are heavy and so they contain an odd heavy ball. Weigh 9 against 10. If they balance, 11 is the odd heavy ball, otherwise the heavier of 9 and 10 is the odd ball.
- If 9, 10, 11 are light, we use the same procedure to reach the same conclusion for the odd light ball.
- 5, 6, 7, 8 are heavy and so either they contain an odd heavy ball or 1, 2, 3, 4 contain an odd light ball. Weigh 1, 2, 5 against 3, 6, 10.
- They balance, so the odd ball is 4 (light) or 7 or 8 (heavy). Thus weigh 7 against 8. If they balance 4 is light, otherwise the heavier of 7 and 8 is the odd heavy ball.
- 3, 6, 10 are heavy, so the odd ball can be 6 (heavy) or 1 or 2 (light). Thus weigh 1 against 2. If they balance 6 is heavy, otherwise the lighter of 1 and 2 is the odd light ball.
- 3, 6, 10 are light, so the odd ball is 3 and light or 5 and heavy. We thus weigh 3 against 10. If they balance 5 is heavy, otherwise 3 is light.
- If 5, 6, 7, 8 are light we use a similar procedure to that in 2.
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Thursday, January 12, 2012
John and Rob's Bank Accounts Balances
John and Rob's bank accounts balances are such that if John gets $400 from Rob they will be in the ratio 2 to 1, but if Rob receives $580 from John, their ratio will be 1 to 4. What are these two guys' balance?
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Answer:
John: $1000 and Rob: $1100
Scroll down to see the answer!
Answer:
John: $1000 and Rob: $1100
How many tourists?
Between 80 and 100 tourists hired a ferryboat for a trip to the sea. Each tourist paid $x.00; where the total was $3589.00. How many tourists were on the ferryboat?
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Answer: 97 tourists.
37 * 97 = 3589
Note that x and the number of tourists both should be integer numbers (no fractions).
Scroll down to see the answer!
Answer: 97 tourists.
37 * 97 = 3589
Note that x and the number of tourists both should be integer numbers (no fractions).
Tuesday, January 10, 2012
Identify the Existing One (Medium)
In the previous post, you did one easy level of "Identify the Existing One". In this post try one medium level!
Study the following four patterns for two minutes:
Study the following four patterns for two minutes:
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Now, look at the following patterns and identify which one looks familiar!
 |
| A |
 |
| B |
 |
| C |
 |
| D |
Answer: D
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Saturday, January 7, 2012
Where are the lieutenants?
In the following camp, five lieutenants are strategically in five different tents. Each tent has a number. The total of numbers for those five tents is 50. The lieutenants' tents are not in horizontal, vertical or diagonal lines.
In 2 minutes, you should identify all the lieutenants' tents!
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Answer:
In 2 minutes, you should identify all the lieutenants' tents!
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Scroll down to see the answer!
Answer:
Thursday, January 5, 2012
Monday, January 2, 2012
Sunday, January 1, 2012
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