At time 1, the variable cost will be 0.7M (boxes) x $2.80 (cost at current prices) x 1.03 (to inflate for 1 year. Total = 2.0188M At time 2, the variable cost will be 1.6M (boxes) x $3.00 (cost at current prices) x 1.03^2 (to inflate for 2 years). Total = 5.09232M Same logic for time 3 and 4
For fixed costs, at time 1 will be 1M x 1.03 (to inflate for 1 year) = 1.03M At time 2 will be 1.8M x 1.03^2 (to inflate for 2 years) = 1.90962 same logic at time 3 and 4.
The free lecture on NPV and inflation will help you.