Initial amount , a = $50 .
Increase in price , d = $25 .
We need to find the recursive relation of the sequence .
If we notice it is an arithmetic progression with common difference $25 .
Which means that difference between any two consecutive term is 25 .
So , T(n) - T(n-1) = 25
T(n) = T(n-1) + 25 .
Hence , this is the required solution .