I am faced with a very problematic wording of a math problem. I can infer what the author meant from the solution, though, I was wandering for the correct linguistic interpretation of the sentence.
Damian needs 1/4 of the wood in the shed on the first day and 2/9 of the remaining wood on the second day to make a tree-house in his backyard. Given that 2/5 of the wood in the shed is unusable due to fungal damage, what fraction of usable wood is left once he has completed the tree-house?
Is that the fraction, (left usable wood)/(total usable wood) or (left usable wood)/(total wood)? does the fact that it is the fraction of 'something' implies that the whole must come from that something?