I think the intended answer is clear once you
assume that the
surcharge is based on the number of days by which the order falls short of the standard 14-day processing time. That gives the official answer of 200%.
However, I feel the wording itself is
ambiguous.The sentence says:
"...
a surcharge of $1 per shirt per day (in addition to the original amount) for each day less than the standard 14-day processing time."
I initially interpreted this as:
If I provide
5 days' less notice, then I pay a
surcharge of $5 per shirt (i.e., $1 for each of the 5 days less of notice).
So the shirt price becomes $4 + $5 = $9.
The official interpretation is:
The surcharge is based on the
shortfall from the standard 14 days.
Therefore, 5 days' notice means 14 − 5 = 9 days short, so the surcharge is $9 per shirt, making the total $13 per shirt.
My issue is that I don't think the parenthetical example completely resolves this ambiguity:
"For instance, 13 days notice would be $5 per shirt, 12 days would be $6 per shirt..."
This example can also be read as referring to the final per-shirt price, not necessarily just illustrating the surcharge rule.
For example:13 days' notice → $4 base + $1 surcharge = $5 per shirt.
12 days' notice → $4 base + $2 surcharge = $6 per shirt.
That example is consistent with both interpretations until we reach a case like 5 days' notice.
I think the wording would have been unambiguous if it had instead said something like:
"
The surcharge is $1 per shirt for each day by which the notice period falls short of 14 days."
or
"
Surcharge = (14 − notice days) × $1 per shirt."
Am I missing something in the grammar, or does anyone else think the original wording could reasonably be interpreted in more than one way ?