Total Won= 0.4n + 1*(35-0.4n)
Total lost = 0.6n (as they need to win all the remaining matches.
Option 1. Total games= 50
i.e. 0.4n + (35-0.4n) +0.6n = 50
0.6n = 15
n= 25 so remaining matches = 50-25 = 25. Hence Sufficient
Option 2. First n lost = 60%
Overall lost = 60%
Hence Remaining lost = 60%
Remaining won = 40%
which is equal to 10
Therefore remaining matches can be calculated as
40% of X = 10
Therefore X = 25
Hence Sufficient
So correct Answer is
Both options alone are sufficient.