A total distance of 1500 m was measured by a 20 m chain. At the end of measuring 500 m distance, the chain is accurate but after measuring a further 1000 m it is found to be 10 cm too long at the end. Determine the exact total length that was measured.
1
1500 m
2
1498.5 m
3
1502.5 m
4
1501 m