The problem of comparing one real output with another and of then calculating net output by setting off new items of equipment against the wastage of old items presents conundrums which permit, one can confidently say, of no solution.

将一项实际产出与另一项实际产出进行比较，然后通过将新设备项目与旧项目的浪费相比较来计算净产出的问题提出了难题，可以自信地说，这些难题无解。