T represents the number of T-Shirts
S represents the number of pairs of socks she bought
Each T-shirt cost $7, so 'T' T-Shirts will cost 7T
Each Pairs of socks cost $2.5, so 'S' pair of socks cost 2.5S

Total cost should be less than or equal to 75 dollars.
Conclusion:
The inequality that would determine the number of T-shirts and pairs of socks she could buy is given below:
