An operator is asked to cut a shallow V-ditch with a 3:1 slope on both sides. If the ditch is to be 0.6 metres deep, what is the approximate total top width of the ditch from shoulder to shoulder?

Question: An operator is asked to cut a shallow V-ditch with a 3:1 slope on both sides. If the ditch is to be 0.6 metres deep, what is the approximate total top width of the ditch from shoulder to shoulder?

Answer options:

• 1.8 metres ✅ 3.6 metres
• 0.6 metres
• 1.2 metres

Correct answer: 3.6 metres

Explanation: A 3:1 slope means for every 1 unit of vertical drop, there are 3 units of horizontal run. For a ditch 0.6 metres deep, the horizontal run on one side would be 3 * 0.6 m = 1.8 metres. Since the V-ditch has two sides, the total top width will be 1.8 m + 1.8 m = 3.6 metres, assuming the bottom is a sharp V-point.