Construction workers were digging a pit for a water storage tank. Each day, the depth of the pit increased by 3 metres as they dug deeper. After five days, they decided to refill the pit with 1 metre of soil to make the base level firm and safe for construction.
Using a number line, determine the final depth of the pit below the ground level.
Starting point: Ground level (0 m)
Digging rate: 3 metres per day (downward = negative)
Duration: 5 days
Total depth dug: 5 × (-3) = -15 metres
Soil refill: +1 metre (upward = positive)
Final calculation: -15 + 1 = -14 metres
Answer: The pit is 14 metres below ground level