Testing Whether Three Witness Accounts Can Stand Together
A bicycle is reported stolen from outside a cloth shop in a bazaar. The complainant says the cycle was chained at 6:40 pm and found missing at 7:10 pm. Three witnesses are examined. W1, a tailor whose shop is 30 m from the cloth shop, says the same young man stood near the cycle at 6:50 pm and rode away towards the culvert at 7:00 pm. W2, a tea seller on the culvert road 1.6 km beyond the cloth shop, says that man sat at his stall from 6:45 pm to 6:58 pm and then left towards the culvert on foot. W3, a shopkeeper 200 m past the cloth shop on the same road, says his wall clock showed 7:12 pm when the man cycled past, and that the clock is known to run ten minutes fast. The investigating officer must decide which statements can stand together before recording them in the case diary.
1. Which two statements cannot both be true, and what assumption about the layout of the bazaar makes them incompatible?
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W1 and W2 cannot both be true.
The assumption is the geography of the road: the tea stall is on the same culvert road, 1.6 km beyond the cloth shop. Anyone cycling from the shop towards the culvert therefore passes the shop first and the tea stall later, not the other way round.
On that layout, W2 puts the man at the stall from 6:45 to 6:58, leaving towards the culvert on foot. W1 puts the same man at the shop from 6:50 to 7:00, riding away at 7:00. He cannot be at the stall and at the shop during the overlapping minutes 6:50 to 6:58. Worse, W2's man is moving away from the shop at 6:58, so he cannot be found at the shop, behind him, two minutes later at 7:00.
Since W1 and W2 describe different positions for the same person in the same minutes, one of them is mistaken, or W2 is describing a different man. That is the conflict the officer must resolve before the case diary shows both statements as if they corroborated each other.
2. Correct W3's time and state whether, after correction, it supports W1 or W2. Show the arithmetic.
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The clock runs ten minutes fast, so the true time is the reading minus the gain: 7:12 pm − 10 minutes = 7:02 pm.
That supports W1. W1 has the man leaving the shop at 7:00 pm; W3's shop is 200 m further along the same road, so the man would pass it at about 7:02 pm. The implied speed over 200 m in 2 minutes is 100 m per minute, that is 6 km/h - slow, but normal for a cycle in a crowded bazaar with pedestrians and handcarts.
It does not support W2, whose account places the man on foot towards the culvert from 6:58 pm and, on the road's layout, ahead of the shop rather than behind it. W1 and W3 therefore corroborate each other on both the direction and the time, and the officer can record them as mutually consistent after the clock correction is noted in the case diary.
3. If W2's account were accepted, what speed would be needed for the man to be at the shop and then at the stall, and what does that tell the investigating officer?
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Accepting W2, the man leaves the stall at 6:58 pm heading towards the culvert. For him to be at the shop afterwards, he would have to travel 1.6 km back to the shop and then be seen there at 7:00 pm - 1.6 km in 2 minutes, which is 48 km/h, impossible for a cycle in a bazaar.
Reverse the direction and the result is no better: 1.6 km from shop to stall in 4 minutes (6:58 to 7:02) is 24 km/h, again beyond a cycle in that traffic.
What this tells the officer is that W2's statement cannot be fitted to the same man on the same bicycle in that window. Either W2 is wrong about the time, or W2 saw a different person, or the vehicle involved was motorised. The case diary should record W1 and W3 as corroborating, record W2's account with the discrepancy worked out in figures rather than in adjectives, re-examine W2, and call for any camera footage on the culvert road to settle which version is right.