Please help me its so confusing

Describe how making an ‘and’ compound sentence effects your solution set

For a function f(x), a) if f(7) = 22 then f^-1(22) = b) f^-1(f(c)) =

Ken earned $128 from his part-time job this summer. he spent 25% of his money on games. he is going to donate 1/6 of the remaining money to charity. how much money will the charity receive?