You can put this solution on YOUR website! Jack runs around the block twice. The block is 1 km long and 500 m wide. How far does he run ?
1 km = 1000 m
Therefore:
2(length + width)
2(1000 + 500)
2 * 1500 = 3000 m
Jack runs the block twice:
3000 * 2 = 6000m