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ArtyomYom
In the third century BC, Greek mathematician and astronomer Eratosthenes calculated the circumference of the Earth to be 252,000 stadia. The stadion (plural: stadia) was a unit of length used in ancient Greece and the value of 1 stadion in terms of later units of length has been the subject of much debate. One belief is that 1 stadion is equivalent to 159.4 metres while another is that 1 stadion equals 185 metres. If the circumference of the Earth is now known to be 24,900 miles (where 1 mile is approximately 1.61 kilometres), depending upon the chosen equivalent measure of a stadion, the error in Erastothenes’ calculation is the closest to

1. 1%-16%
2. 15%-75%
3. 84%-99%
4. 523%-621%
5. 98896%-118121%

Solution:

Case 1. If 1 stadion = 159.4 meters, then the circumference of the Earth is 252,000 x 159.4 = 40,168,800 meters, which is 40,168.8 km or 40,168.8/1.61 ≈ 24,950 miles.

Case 2. If 1 stadion = 185 meters, then the circumference of the Earth is 252,000 x 185 = 46,620,000 meters, which is 46,620 km or 46,620/1.61 ≈ 28,957 miles.

Using the Case 1 measurement, we see that the circumference of the Earth is off by approximately 50 miles, and using the Case 2 measurement, we see that the circumference is off by approximately 4,057 milles. By looking at the given choices, we see that answer choice 1 is the best approximation of the error in Eratosthenes' calculation of the circumference of the Earth (notice that 50 mies is actually less than 1% of 24,900 miles and 4,057 miles is more than 10% but less than 20% of 24,900 miles).

Answer: 1
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Bunuel please help with this stuck at ending couldn't calculate the percent difference
ArtyomYom
In the third century BC, Greek mathematician and astronomer Eratosthenes calculated the circumference of the Earth to be 252,000 stadia. The stadion (plural: stadia) was a unit of length used in ancient Greece and the value of 1 stadion in terms of later units of length has been the subject of much debate. One belief is that 1 stadion is equivalent to 159.4 metres while another is that 1 stadion equals 185 metres. If the circumference of the Earth is now known to be 24,900 miles (where 1 mile is approximately 1.61 kilometres), depending upon the chosen equivalent measure of a stadion, the error in Erastothenes’ calculation is the closest to

1. 1%-16%
2. 15%-75%
3. 84%-99%
4. 523%-621%
5. 98896%-118121%
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Bunuel please help with this stuck at ending couldn't calculate the percent difference
ArtyomYom
In the third century BC, Greek mathematician and astronomer Eratosthenes calculated the circumference of the Earth to be 252,000 stadia. The stadion (plural: stadia) was a unit of length used in ancient Greece and the value of 1 stadion in terms of later units of length has been the subject of much debate. One belief is that 1 stadion is equivalent to 159.4 metres while another is that 1 stadion equals 185 metres. If the circumference of the Earth is now known to be 24,900 miles (where 1 mile is approximately 1.61 kilometres), depending upon the chosen equivalent measure of a stadion, the error in Erastothenes’ calculation is the closest to

1. 1%-16%
2. 15%-75%
3. 84%-99%
4. 523%-621%
5. 98896%-118121%
You don't need to calculate perfect difference.

So, we are given that 24900 * 1610 metres is correct circumference.

Now, Era's calculated circumference could be => 252000 * 159.4 = 25200 * 1594 metres...(i) or 252000 * 185 = 2520 * 1850 metres...(ii)

So, comparing (i) and correct circumference, 24900 and 25200 seem close so we cann ignore that, now difference between 1610 and 1594 is 16 => 16/1610 ~ 1%

Using approximation will be the correct approach here.
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