Puzzle 153
How should these words actually be spelled, without using a dictionary.
bizz-ness
com-it-ee
sin-seer-lee
ark-ee-ollow-jist
Puzzle Copyright © Kevin Stone
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Hint
Be careful with the middle of the last word.
Answer
Business.
Committee.
Sincerely.
Archaeologist.
Puzzle 154
Can you find three consecutive odd numbers that …
… total 1,287 when multiplied together?
Puzzle Copyright © Kevin Stone
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Hint
There are two different methods, one involves a cube root, and the other doesn't require a calculator.
Answer
9 x 11 x 13.
Reasoning #1
We're after three numbers that multiply together, so a good place to start is the cube root of 1,287, which is roughly 10.88.
Let's try dividing by the closest odd number to 10.88:
1287 ÷ 11 = 117
We're now after whole divisors of 117. Trying the odd numbers either side of 11 might work.
Trying either 9 or 13 gives the answer:
9 x 11 x 13 = 1,287
Trying the closest odd number to the cube root always works, and the other two numbers are the odd numbers either side.
Reasoning #2
We after three numbers that multiply together, but none of these can end in 5 (otherwise our answer would end in 0 or 5).
So, they can only end in 7, 9, 1 (e.g. 87, 89, 91), or 9, 1, 3 (e.g. 89, 91, 93).
However, if they ended in 7, 9, 1, the answer would end in 3 (because 7 x 9 x 1 = 63).
Therefore, they end in 9, 1, and 3 (because 9 x 1 x 3 = 27).
The first numbers we can try are 9, 11, 13:
= 9 x 11 x 13
= 99 x 13
= 100 x 13 − 13
= 1300 − 13
= 1,287
A calculator is not required!
Puzzle 155
This BrainBashers safe has a rather unusual control panel.
In order to open the safe, you have to press every single square once only, in the correct sequence, ending on the square marked E.
Each square indicates which square to press next, for example, 2U means move up 2 squares and 3R means move right 3 squares.
Can you determine which square you must start with?
| 4R |
4D |
1R |
1D |
2D |
4L |
1D |
| 1R |
4D |
5D |
2R |
2D |
1L |
4L |
| 2R |
1D |
1L |
2R |
2R |
2D |
2U |
| 2R |
2R |
3U |
3D |
1R |
3U |
6L |
| 3U |
3R |
1D |
2U |
4L |
2D |
3L |
| 3U |
1L |
1R |
1R |
1R |
1R |
2U |
| 6U |
E |
2U |
2L |
4L |
1L |
2U |
Note: this puzzle is not interactive, and the safe buttons cannot be clicked.
Puzzle Copyright © Kevin Stone
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Hint
Start on any square, and see how far you can get.
Answer
Start from the 2U in the bottom right-hand corner.
Puzzle 156
What number comes next in this sequence:
986888
724864
143224
==??==
Puzzle Copyright © Kevin Stone
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Hint
The answer involves multiplication (for example, 9 x 8 = 72).
Answer
468.
Reasoning
If we split each line in the following way:
98 68 88
72 48 64
14 32 24
Each new line is generated by multiplying the digits two at a time and writing the result below.
For example, 9 x 8 = 72, so 72 appears directly below 98.
And 7 x 2 = 14, so 14 appears directly below 72.
Double-Checking
9 x 8 = 72 and 7 x 2 = 14.
6 x 8 = 48 and 4 x 8 = 32.
8 x 8 = 64 and 6 x 4 = 24.