marking scheme of examiner

In march 2024 AFM exam, there is a problem requiring the calculation of NPV of cash flow X from year 11 to infinity, which increase at rate of 7% and at cost of capital of 12% to the net present value (NPV). I want to ask if a make a mistake, for example, calculate NPV in abbrivated form (due to time pressure I must have to write in abbrivated form) as: NPV= X*(1+7%)*1.12^(-5)/(12%-7%) instead of NPV =X*(1+7%)*1.12^(-11)/(12%-7%), can I have mark for the part of calculation of PV of cash flow to annuity discounted to year 11 as: X*(1+7%)/(12%-7%)?

Thanks!