Reasoning
We know that (answer − 1) is divisible by 3, 5, 7, and 9.
If it's divisible by 9 then it's automatically divisible by 3.
So the number must be a multiple of 5, 7, and 9.
[5 x 7 x 9 = 315]
Since these numbers share no other common factors, we know that the answer must be a multiple of 315 (+ 1).
Let's try 1 x 315 + 1: 316 ÷ 11 = 28.73, and this doesn't work.
Let's try 2 x 315 + 1: 631 ÷ 11 = 57.36, and this doesn't work.
Let's try 3 x 315 + 1: 946 ÷ 11 = 86, and this works, and is the answer.
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Puzzle 110
The local River Trent is 4,100 inches wide, which happens to be a fantastic number.
There is a magnificent, perfectly straight, bridge that spans the river at right angles.
During a recent survey of the area, it was found that one-seventh of the overall length of the bridge was on one bank of the river, and one-eighth of the bridge was on the other bank.
What is the total length of the bridge that spans the River Trent?
Hint
Try fixing the number of children to see what happens.
Answer
92.
With 149 men and 259 women. The best way is to fix the number of children and play around with the numbers of the men and women to see what happens as these are changed. It soon becomes apparent how changing the children changes the answer and 92 is soon found.
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Puzzle 112
The Winter Festival is well underway and BrainBashers control is working out the plane times for the return journeys.
Unfortunately, the BrainBashers timetable software is playing up again and has worked out the times incorrectly, as shown below.
France 4.00pm
Mexico 3.00pm
Jamaica 5.00pm
Japan 1.00pm
According to the software, at what time is the return trip to Finland?
