Past Exam 2019 MarJun Quesion 32 – (a)(ii) appraising investment project

Hi Sir,

This questions about appraising investment project.
Like normal, we have sale price/ variable cost/ fixed cost/ selling quantities for 4 years
Each of the above have inflation rate.
and 12% is nominal after tax cost of capital and 8% is after tax cost of capital.

(a – i ) calculate Nominal NPV
(b – i ) Real NPV

for (a-i) I can do correctly however for (b-i) I dont understand how to calculate the Real Cash flows before tax as same as in the answer key.

The way I do was just use (sale price – variable cost) * quantities – fixed cost without using any inflation rate. However it seem like not correct with the answer.
Appreciate your help to explain me the calculation of REAL CASH FLOW BEFORE TAX