Well assuming they are sharing the workload and worker B isn't just digging half a hole while worker A digs a whole hole, I would say 3/4 of a day assuming they work at an equal intensity. However, many variables should be taken into account: Type of spade used, weather condition, hardness of the ground, effectiveness of the workers as well as whether they had their Weetabix that morning.
Of course this is not a mathematical problem though - it is impossible to dig half a hole, unless there is a fixed dimension of the hole. Anyone who has seen the film 'Holes' will know that their holes had to be a spade deep and a spade in diameter. Assuming this is what the Cymro implied then the answer would indeed be 3/4 as we have a fixed volume. Although as this is not stated in the question I would have to conclude that it is impossible to ascertain an answer.
Essentially, if we take this problem and relate it to the parallel of what Cymro is attempting to draw, he believes that more information will be released on 16/4/11 at 14:32.
