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?
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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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