It is: 215 that rounds off to 220 to the nearest ten
The answer depends on the degree of rounding. To the nearest integer (unit) it is 215. To the nearest hundred it is 200. To the nearest thousand, it is 0.
0
200
220
200
The Thames' length is 346,010 meters.
If 43 is one-tenth of the answer, then the answer is 430. If you divide 430 by 2, the original number was 215.
215 miles
220
215
The River Thames is approximately 215 miles (346 kilometers) long.