Answer: Tine solved 15 hard puzzles.
Step-by-step explanation:
Let x be the number of easy puzzles and y be the number of hard puzzels.
Given : A player earns 30 points for solving an easy puzzles and 60 points for solving a hard puzzled.
Tina solved a total of 50 Puzzles playing this game, earning 1950 points in all.
Then system of equations for above description:

Multiply 60 in equation (1), we get

Subtract equation (2) from (3), we get

Put x=-35 in (1), we get

Hence, Tine solved 15 hard puzzles.