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
What fraction of the length of the bridge is on the banks?
Answer
5,600 inches.
Reasoning
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.
??
Puzzle 199
My BrainBashers electronic world atlas has developed another fault.
I listed five countries, and how far away each was from England, and here are the results:
Australia 500 miles
Peru 8,000 miles
India 4,500 miles
Scotland 9,500 miles
France ? miles
