Add 60, 200 and 120 together. After adding this, you would get 380. Since it asks how much money he has 'left', you subtract 380 from 525, which gives you 145.
The value of g^-1(-3) is the value of x that makes g(x) = -3. To find it, we can solve .. (x +4)/(2x -5) = -3 .. x +4 = -3(2x -5) .. 7x = 11 .. x = 11/7
The desired value is .. (3/11)*g^-1(-3) .. = (3/11)*(11/7) .. = 3/7