At any given moment of time, a snapshot could be taken of this arrow. In this snapshot, the arrow would not be moving. Let us now take another snapshot, leaving a very small gap of time between them. Again, the arrow is stationary. We can keep taking snapshots for each moment of time, each of which shows the arrow to be stationary. Therefore the overall effect is that the arrow never moves, however it still hits the target!
This is a classic paradox, attributed to Zeno of Elea, a Greek philosopher from Italy. Great minds over the centuries have pondered this paradox, and the scope of a solution is beyond the space available here. It is not even clear that a solution to the paradox actually exists.
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Puzzle 2
I have a jar of sweets that contains 114 red, 35 blue, 67 green, and 9 yellow.
What chance do I have of picking a yellow sweet with my eyes shut?
Hint
How many yellow sweets are there, how many sweets in total?
Answer
1 in 25 = 4 percent.
Reasoning
In total, there are 114 + 35 + 67 + 9 = 225 sweets.
There are 9 yellow sweets, so the probability is 9 ÷ 225 = 0.04 = 4% = 1 in 25.
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Puzzle 3
Last week I travelled from London to Leeds, a distance I measured as 174 miles.
I started at 9.15am and completed the journey with an average speed of 40 miles per hour.
On the way back, in the evening, I travelled exactly the same route, starting at 5.15pm. The traffic was light, and I completed the journey with an average speed of 60 miles per hour.
What was the overall average speed for the round trip?
