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Puzzle ZOWY 



??

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?

Puzzle Copyright © Kevin Stone

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Answer
5,600 inches.

We know that 1÷7 + 1÷8 of the total length is on the banks of the river, and 1÷7 + 1÷8 = 15÷56.

So the river width (4,100 inches) is the remaining 41÷56 of the bridge.

Therefore:

   41÷56 x length = 4100

So:

   length          = 4100 x 56÷41

   length          = 5600

As required.

 

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